11da177e4SLinus Torvalds/* 21da177e4SLinus Torvalds * Linux/PA-RISC Project (http://www.parisc-linux.org/) 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * System call entry code Copyright (c) Matthew Wilcox 1999 <willy@bofh.ai> 51da177e4SLinus Torvalds * Licensed under the GNU GPL. 61da177e4SLinus Torvalds * thanks to Philipp Rumpf, Mike Shaver and various others 71da177e4SLinus Torvalds * sorry about the wall, puffin.. 81da177e4SLinus Torvalds */ 91da177e4SLinus Torvalds 101da177e4SLinus Torvalds#include <asm/offsets.h> 111da177e4SLinus Torvalds#include <asm/unistd.h> 121da177e4SLinus Torvalds#include <asm/errno.h> 131da177e4SLinus Torvalds#include <asm/psw.h> 141da177e4SLinus Torvalds#include <asm/thread_info.h> 151da177e4SLinus Torvalds 161da177e4SLinus Torvalds#include <asm/assembly.h> 171da177e4SLinus Torvalds#include <asm/processor.h> 181da177e4SLinus Torvalds 191da177e4SLinus Torvalds /* We fill the empty parts of the gateway page with 201da177e4SLinus Torvalds * something that will kill the kernel or a 211da177e4SLinus Torvalds * userspace application. 221da177e4SLinus Torvalds */ 231da177e4SLinus Torvalds#define KILL_INSN break 0,0 241da177e4SLinus Torvalds 251da177e4SLinus Torvalds#include <linux/config.h> /* for CONFIG_SMP */ 261da177e4SLinus Torvalds 271da177e4SLinus Torvalds#ifdef __LP64__ 281da177e4SLinus Torvalds .level 2.0w 291da177e4SLinus Torvalds#else 301da177e4SLinus Torvalds .level 1.1 311da177e4SLinus Torvalds#endif 321da177e4SLinus Torvalds 331da177e4SLinus Torvalds#ifndef __LP64__ 341da177e4SLinus Torvalds .macro fixup_branch,lbl 351da177e4SLinus Torvalds b \lbl 361da177e4SLinus Torvalds .endm 371da177e4SLinus Torvalds#else 381da177e4SLinus Torvalds .macro fixup_branch,lbl 391da177e4SLinus Torvalds ldil L%\lbl, %r1 401da177e4SLinus Torvalds ldo R%\lbl(%r1), %r1 411da177e4SLinus Torvalds bv,n %r0(%r1) 421da177e4SLinus Torvalds .endm 431da177e4SLinus Torvalds#endif 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds .text 461da177e4SLinus Torvalds 471da177e4SLinus Torvalds .import syscall_exit,code 481da177e4SLinus Torvalds .import syscall_exit_rfi,code 491da177e4SLinus Torvalds .export linux_gateway_page 501da177e4SLinus Torvalds 511da177e4SLinus Torvalds /* Linux gateway page is aliased to virtual page 0 in the kernel 521da177e4SLinus Torvalds * address space. Since it is a gateway page it cannot be 531da177e4SLinus Torvalds * dereferenced, so null pointers will still fault. We start 541da177e4SLinus Torvalds * the actual entry point at 0x100. We put break instructions 551da177e4SLinus Torvalds * at the beginning of the page to trap null indirect function 561da177e4SLinus Torvalds * pointers. 571da177e4SLinus Torvalds */ 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds .align 4096 601da177e4SLinus Torvaldslinux_gateway_page: 611da177e4SLinus Torvalds 621da177e4SLinus Torvalds /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */ 631da177e4SLinus Torvalds .rept 44 641da177e4SLinus Torvalds KILL_INSN 651da177e4SLinus Torvalds .endr 661da177e4SLinus Torvalds 671da177e4SLinus Torvalds /* ADDRESS 0xb0 to 0xb4, lws uses 1 insns for entry */ 681da177e4SLinus Torvalds /* Light-weight-syscall entry must always be located at 0xb0 */ 691da177e4SLinus Torvalds /* WARNING: Keep this number updated with table size changes */ 701da177e4SLinus Torvalds#define __NR_lws_entries (2) 711da177e4SLinus Torvalds 721da177e4SLinus Torvaldslws_entry: 731da177e4SLinus Torvalds /* Unconditional branch to lws_start, located on the 741da177e4SLinus Torvalds same gateway page */ 751da177e4SLinus Torvalds b,n lws_start 761da177e4SLinus Torvalds 771da177e4SLinus Torvalds /* Fill from 0xb4 to 0xe0 */ 781da177e4SLinus Torvalds .rept 11 791da177e4SLinus Torvalds KILL_INSN 801da177e4SLinus Torvalds .endr 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds /* This function MUST be located at 0xe0 for glibc's threading 831da177e4SLinus Torvalds mechanism to work. DO NOT MOVE THIS CODE EVER! */ 841da177e4SLinus Torvaldsset_thread_pointer: 851da177e4SLinus Torvalds gate .+8, %r0 /* increase privilege */ 861da177e4SLinus Torvalds depi 3, 31, 2, %r31 /* Ensure we return into user mode. */ 871da177e4SLinus Torvalds be 0(%sr7,%r31) /* return to user space */ 881da177e4SLinus Torvalds mtctl %r26, %cr27 /* move arg0 to the control register */ 891da177e4SLinus Torvalds 901da177e4SLinus Torvalds /* Increase the chance of trapping if random jumps occur to this 911da177e4SLinus Torvalds address, fill from 0xf0 to 0x100 */ 921da177e4SLinus Torvalds .rept 4 931da177e4SLinus Torvalds KILL_INSN 941da177e4SLinus Torvalds .endr 951da177e4SLinus Torvalds 961da177e4SLinus Torvalds/* This address must remain fixed at 0x100 for glibc's syscalls to work */ 971da177e4SLinus Torvalds .align 256 981da177e4SLinus Torvaldslinux_gateway_entry: 991da177e4SLinus Torvalds gate .+8, %r0 /* become privileged */ 1001da177e4SLinus Torvalds mtsp %r0,%sr4 /* get kernel space into sr4 */ 1011da177e4SLinus Torvalds mtsp %r0,%sr5 /* get kernel space into sr5 */ 1021da177e4SLinus Torvalds mtsp %r0,%sr6 /* get kernel space into sr6 */ 1031da177e4SLinus Torvalds mfsp %sr7,%r1 /* save user sr7 */ 1041da177e4SLinus Torvalds mtsp %r1,%sr3 /* and store it in sr3 */ 1051da177e4SLinus Torvalds 1061da177e4SLinus Torvalds#ifdef __LP64__ 1071da177e4SLinus Torvalds /* for now we can *always* set the W bit on entry to the syscall 1081da177e4SLinus Torvalds * since we don't support wide userland processes. We could 1091da177e4SLinus Torvalds * also save the current SM other than in r0 and restore it on 1101da177e4SLinus Torvalds * exit from the syscall, and also use that value to know 1111da177e4SLinus Torvalds * whether to do narrow or wide syscalls. -PB 1121da177e4SLinus Torvalds */ 1131da177e4SLinus Torvalds ssm PSW_SM_W, %r1 1141da177e4SLinus Torvalds extrd,u %r1,PSW_W_BIT,1,%r1 1151da177e4SLinus Torvalds /* sp must be aligned on 4, so deposit the W bit setting into 1161da177e4SLinus Torvalds * the bottom of sp temporarily */ 1171da177e4SLinus Torvalds or,ev %r1,%r30,%r30 1181da177e4SLinus Torvalds b,n 1f 1191da177e4SLinus Torvalds /* The top halves of argument registers must be cleared on syscall 1201da177e4SLinus Torvalds * entry from narrow executable. 1211da177e4SLinus Torvalds */ 1221da177e4SLinus Torvalds depdi 0, 31, 32, %r26 1231da177e4SLinus Torvalds depdi 0, 31, 32, %r25 1241da177e4SLinus Torvalds depdi 0, 31, 32, %r24 1251da177e4SLinus Torvalds depdi 0, 31, 32, %r23 1261da177e4SLinus Torvalds depdi 0, 31, 32, %r22 1271da177e4SLinus Torvalds depdi 0, 31, 32, %r21 1281da177e4SLinus Torvalds1: 1291da177e4SLinus Torvalds#endif 1301da177e4SLinus Torvalds mfctl %cr30,%r1 1311da177e4SLinus Torvalds xor %r1,%r30,%r30 /* ye olde xor trick */ 1321da177e4SLinus Torvalds xor %r1,%r30,%r1 1331da177e4SLinus Torvalds xor %r1,%r30,%r30 1341da177e4SLinus Torvalds 1351da177e4SLinus Torvalds ldo THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30 /* set up kernel stack */ 1361da177e4SLinus Torvalds 1371da177e4SLinus Torvalds /* N.B.: It is critical that we don't set sr7 to 0 until r30 1381da177e4SLinus Torvalds * contains a valid kernel stack pointer. It is also 1391da177e4SLinus Torvalds * critical that we don't start using the kernel stack 1401da177e4SLinus Torvalds * until after sr7 has been set to 0. 1411da177e4SLinus Torvalds */ 1421da177e4SLinus Torvalds 1431da177e4SLinus Torvalds mtsp %r0,%sr7 /* get kernel space into sr7 */ 1441da177e4SLinus Torvalds STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */ 1451da177e4SLinus Torvalds mfctl %cr30,%r1 /* get task ptr in %r1 */ 1461da177e4SLinus Torvalds LDREG TI_TASK(%r1),%r1 1471da177e4SLinus Torvalds 1481da177e4SLinus Torvalds /* Save some registers for sigcontext and potential task 1491da177e4SLinus Torvalds switch (see entry.S for the details of which ones are 1501da177e4SLinus Torvalds saved/restored). TASK_PT_PSW is zeroed so we can see whether 1511da177e4SLinus Torvalds a process is on a syscall or not. For an interrupt the real 1521da177e4SLinus Torvalds PSW value is stored. This is needed for gdb and sys_ptrace. */ 1531da177e4SLinus Torvalds STREG %r0, TASK_PT_PSW(%r1) 1541da177e4SLinus Torvalds STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */ 1551da177e4SLinus Torvalds STREG %r19, TASK_PT_GR19(%r1) 1561da177e4SLinus Torvalds 1571da177e4SLinus Torvalds LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */ 1581da177e4SLinus Torvalds#ifdef __LP64__ 1591da177e4SLinus Torvalds extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */ 1601da177e4SLinus Torvalds#if 0 1611da177e4SLinus Torvalds xor %r19,%r2,%r2 /* clear bottom bit */ 1621da177e4SLinus Torvalds depd,z %r19,1,1,%r19 1631da177e4SLinus Torvalds std %r19,TASK_PT_PSW(%r1) 1641da177e4SLinus Torvalds#endif 1651da177e4SLinus Torvalds#endif 1661da177e4SLinus Torvalds STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */ 1671da177e4SLinus Torvalds 1681da177e4SLinus Torvalds STREG %r20, TASK_PT_GR20(%r1) 1691da177e4SLinus Torvalds STREG %r21, TASK_PT_GR21(%r1) 1701da177e4SLinus Torvalds STREG %r22, TASK_PT_GR22(%r1) 1711da177e4SLinus Torvalds STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */ 1721da177e4SLinus Torvalds STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */ 1731da177e4SLinus Torvalds STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */ 1741da177e4SLinus Torvalds STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */ 1751da177e4SLinus Torvalds STREG %r27, TASK_PT_GR27(%r1) /* user dp */ 1761da177e4SLinus Torvalds STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */ 1771da177e4SLinus Torvalds STREG %r28, TASK_PT_ORIG_R28(%r1) /* return value 0 (saved for signals) */ 1781da177e4SLinus Torvalds STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */ 1791da177e4SLinus Torvalds STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */ 1801da177e4SLinus Torvalds 1811da177e4SLinus Torvalds ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */ 1821da177e4SLinus Torvalds save_fp %r27 /* or potential task switch */ 1831da177e4SLinus Torvalds 1841da177e4SLinus Torvalds mfctl %cr11, %r27 /* i.e. SAR */ 1851da177e4SLinus Torvalds STREG %r27, TASK_PT_SAR(%r1) 1861da177e4SLinus Torvalds 1871da177e4SLinus Torvalds loadgp 1881da177e4SLinus Torvalds 1891da177e4SLinus Torvalds#ifdef __LP64__ 1901da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 1911da177e4SLinus Torvalds copy %r19,%r2 /* W bit back to r2 */ 1921da177e4SLinus Torvalds#else 1931da177e4SLinus Torvalds /* no need to save these on stack in wide mode because the first 8 1941da177e4SLinus Torvalds * args are passed in registers */ 1951da177e4SLinus Torvalds stw %r22, -52(%r30) /* 5th argument */ 1961da177e4SLinus Torvalds stw %r21, -56(%r30) /* 6th argument */ 1971da177e4SLinus Torvalds#endif 1981da177e4SLinus Torvalds 1991da177e4SLinus Torvalds /* Are we being ptraced? */ 2001da177e4SLinus Torvalds mfctl %cr30, %r1 2011da177e4SLinus Torvalds LDREG TI_TASK(%r1),%r1 2021da177e4SLinus Torvalds LDREG TASK_PTRACE(%r1), %r1 2031da177e4SLinus Torvalds bb,<,n %r1,31,.Ltracesys 2041da177e4SLinus Torvalds 2051da177e4SLinus Torvalds /* Note! We cannot use the syscall table that is mapped 2061da177e4SLinus Torvalds nearby since the gateway page is mapped execute-only. */ 2071da177e4SLinus Torvalds 2081da177e4SLinus Torvalds#ifdef __LP64__ 2091da177e4SLinus Torvalds ldil L%sys_call_table, %r1 2101da177e4SLinus Torvalds or,= %r2,%r2,%r2 2111da177e4SLinus Torvalds addil L%(sys_call_table64-sys_call_table), %r1 2121da177e4SLinus Torvalds ldo R%sys_call_table(%r1), %r19 2131da177e4SLinus Torvalds or,= %r2,%r2,%r2 2141da177e4SLinus Torvalds ldo R%sys_call_table64(%r1), %r19 2151da177e4SLinus Torvalds#else 2161da177e4SLinus Torvalds ldil L%sys_call_table, %r1 2171da177e4SLinus Torvalds ldo R%sys_call_table(%r1), %r19 2181da177e4SLinus Torvalds#endif 2191da177e4SLinus Torvalds comiclr,>>= __NR_Linux_syscalls, %r20, %r0 2201da177e4SLinus Torvalds b,n .Lsyscall_nosys 2211da177e4SLinus Torvalds 2221da177e4SLinus Torvalds LDREGX %r20(%r19), %r19 2231da177e4SLinus Torvalds 2241da177e4SLinus Torvalds /* If this is a sys_rt_sigreturn call, and the signal was received 2251da177e4SLinus Torvalds * when not in_syscall, then we want to return via syscall_exit_rfi, 2261da177e4SLinus Torvalds * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 2271da177e4SLinus Torvalds * trampoline code in signal.c). 2281da177e4SLinus Torvalds */ 2291da177e4SLinus Torvalds ldi __NR_rt_sigreturn,%r2 2301da177e4SLinus Torvalds comb,= %r2,%r20,.Lrt_sigreturn 2311da177e4SLinus Torvalds.Lin_syscall: 2321da177e4SLinus Torvalds ldil L%syscall_exit,%r2 2331da177e4SLinus Torvalds be 0(%sr7,%r19) 2341da177e4SLinus Torvalds ldo R%syscall_exit(%r2),%r2 2351da177e4SLinus Torvalds.Lrt_sigreturn: 2361da177e4SLinus Torvalds comib,<> 0,%r25,.Lin_syscall 2371da177e4SLinus Torvalds ldil L%syscall_exit_rfi,%r2 2381da177e4SLinus Torvalds be 0(%sr7,%r19) 2391da177e4SLinus Torvalds ldo R%syscall_exit_rfi(%r2),%r2 2401da177e4SLinus Torvalds 2411da177e4SLinus Torvalds /* Note! Because we are not running where we were linked, any 2421da177e4SLinus Torvalds calls to functions external to this file must be indirect. To 2431da177e4SLinus Torvalds be safe, we apply the opposite rule to functions within this 2441da177e4SLinus Torvalds file, with local labels given to them to ensure correctness. */ 2451da177e4SLinus Torvalds 2461da177e4SLinus Torvalds.Lsyscall_nosys: 2471da177e4SLinus Torvaldssyscall_nosys: 2481da177e4SLinus Torvalds ldil L%syscall_exit,%r1 2491da177e4SLinus Torvalds be R%syscall_exit(%sr7,%r1) 2501da177e4SLinus Torvalds ldo -ENOSYS(%r0),%r28 /* set errno */ 2511da177e4SLinus Torvalds 2521da177e4SLinus Torvalds 2531da177e4SLinus Torvalds/* Warning! This trace code is a virtual duplicate of the code above so be 2541da177e4SLinus Torvalds * sure to maintain both! */ 2551da177e4SLinus Torvalds.Ltracesys: 2561da177e4SLinus Torvaldstracesys: 2571da177e4SLinus Torvalds /* Need to save more registers so the debugger can see where we 2581da177e4SLinus Torvalds * are. This saves only the lower 8 bits of PSW, so that the C 2591da177e4SLinus Torvalds * bit is still clear on syscalls, and the D bit is set if this 2601da177e4SLinus Torvalds * full register save path has been executed. We check the D 2611da177e4SLinus Torvalds * bit on syscall_return_rfi to determine which registers to 2621da177e4SLinus Torvalds * restore. An interrupt results in a full PSW saved with the 2631da177e4SLinus Torvalds * C bit set, a non-straced syscall entry results in C and D clear 2641da177e4SLinus Torvalds * in the saved PSW. 2651da177e4SLinus Torvalds */ 2661da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 2671da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 2681da177e4SLinus Torvalds ssm 0,%r2 2691da177e4SLinus Torvalds STREG %r2,TASK_PT_PSW(%r1) /* Lower 8 bits only!! */ 2701da177e4SLinus Torvalds mfsp %sr0,%r2 2711da177e4SLinus Torvalds STREG %r2,TASK_PT_SR0(%r1) 2721da177e4SLinus Torvalds mfsp %sr1,%r2 2731da177e4SLinus Torvalds STREG %r2,TASK_PT_SR1(%r1) 2741da177e4SLinus Torvalds mfsp %sr2,%r2 2751da177e4SLinus Torvalds STREG %r2,TASK_PT_SR2(%r1) 2761da177e4SLinus Torvalds mfsp %sr3,%r2 2771da177e4SLinus Torvalds STREG %r2,TASK_PT_SR3(%r1) 2781da177e4SLinus Torvalds STREG %r2,TASK_PT_SR4(%r1) 2791da177e4SLinus Torvalds STREG %r2,TASK_PT_SR5(%r1) 2801da177e4SLinus Torvalds STREG %r2,TASK_PT_SR6(%r1) 2811da177e4SLinus Torvalds STREG %r2,TASK_PT_SR7(%r1) 2821da177e4SLinus Torvalds STREG %r2,TASK_PT_IASQ0(%r1) 2831da177e4SLinus Torvalds STREG %r2,TASK_PT_IASQ1(%r1) 2841da177e4SLinus Torvalds LDREG TASK_PT_GR31(%r1),%r2 2851da177e4SLinus Torvalds STREG %r2,TASK_PT_IAOQ0(%r1) 2861da177e4SLinus Torvalds ldo 4(%r2),%r2 2871da177e4SLinus Torvalds STREG %r2,TASK_PT_IAOQ1(%r1) 2881da177e4SLinus Torvalds ldo TASK_REGS(%r1),%r2 2891da177e4SLinus Torvalds /* reg_save %r2 */ 2901da177e4SLinus Torvalds STREG %r3,PT_GR3(%r2) 2911da177e4SLinus Torvalds STREG %r4,PT_GR4(%r2) 2921da177e4SLinus Torvalds STREG %r5,PT_GR5(%r2) 2931da177e4SLinus Torvalds STREG %r6,PT_GR6(%r2) 2941da177e4SLinus Torvalds STREG %r7,PT_GR7(%r2) 2951da177e4SLinus Torvalds STREG %r8,PT_GR8(%r2) 2961da177e4SLinus Torvalds STREG %r9,PT_GR9(%r2) 2971da177e4SLinus Torvalds STREG %r10,PT_GR10(%r2) 2981da177e4SLinus Torvalds STREG %r11,PT_GR11(%r2) 2991da177e4SLinus Torvalds STREG %r12,PT_GR12(%r2) 3001da177e4SLinus Torvalds STREG %r13,PT_GR13(%r2) 3011da177e4SLinus Torvalds STREG %r14,PT_GR14(%r2) 3021da177e4SLinus Torvalds STREG %r15,PT_GR15(%r2) 3031da177e4SLinus Torvalds STREG %r16,PT_GR16(%r2) 3041da177e4SLinus Torvalds STREG %r17,PT_GR17(%r2) 3051da177e4SLinus Torvalds STREG %r18,PT_GR18(%r2) 3061da177e4SLinus Torvalds /* Finished saving things for the debugger */ 3071da177e4SLinus Torvalds 3081da177e4SLinus Torvalds ldil L%syscall_trace,%r1 3091da177e4SLinus Torvalds ldil L%tracesys_next,%r2 3101da177e4SLinus Torvalds be R%syscall_trace(%sr7,%r1) 3111da177e4SLinus Torvalds ldo R%tracesys_next(%r2),%r2 3121da177e4SLinus Torvalds 3131da177e4SLinus Torvaldstracesys_next: 3141da177e4SLinus Torvalds ldil L%sys_call_table,%r1 3151da177e4SLinus Torvalds ldo R%sys_call_table(%r1), %r19 3161da177e4SLinus Torvalds 3171da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3181da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 3191da177e4SLinus Torvalds LDREG TASK_PT_GR20(%r1), %r20 3201da177e4SLinus Torvalds LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */ 3211da177e4SLinus Torvalds LDREG TASK_PT_GR25(%r1), %r25 3221da177e4SLinus Torvalds LDREG TASK_PT_GR24(%r1), %r24 3231da177e4SLinus Torvalds LDREG TASK_PT_GR23(%r1), %r23 3241da177e4SLinus Torvalds#ifdef __LP64__ 3251da177e4SLinus Torvalds LDREG TASK_PT_GR22(%r1), %r22 3261da177e4SLinus Torvalds LDREG TASK_PT_GR21(%r1), %r21 3271da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3281da177e4SLinus Torvalds#endif 3291da177e4SLinus Torvalds 3301da177e4SLinus Torvalds comiclr,>>= __NR_Linux_syscalls, %r20, %r0 3311da177e4SLinus Torvalds b,n .Lsyscall_nosys 3321da177e4SLinus Torvalds 3331da177e4SLinus Torvalds LDREGX %r20(%r19), %r19 3341da177e4SLinus Torvalds 3351da177e4SLinus Torvalds /* If this is a sys_rt_sigreturn call, and the signal was received 3361da177e4SLinus Torvalds * when not in_syscall, then we want to return via syscall_exit_rfi, 3371da177e4SLinus Torvalds * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 3381da177e4SLinus Torvalds * trampoline code in signal.c). 3391da177e4SLinus Torvalds */ 3401da177e4SLinus Torvalds ldi __NR_rt_sigreturn,%r2 3411da177e4SLinus Torvalds comb,= %r2,%r20,.Ltrace_rt_sigreturn 3421da177e4SLinus Torvalds.Ltrace_in_syscall: 3431da177e4SLinus Torvalds ldil L%tracesys_exit,%r2 3441da177e4SLinus Torvalds be 0(%sr7,%r19) 3451da177e4SLinus Torvalds ldo R%tracesys_exit(%r2),%r2 3461da177e4SLinus Torvalds 3471da177e4SLinus Torvalds /* Do *not* call this function on the gateway page, because it 3481da177e4SLinus Torvalds makes a direct call to syscall_trace. */ 3491da177e4SLinus Torvalds 3501da177e4SLinus Torvaldstracesys_exit: 3511da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3521da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 3531da177e4SLinus Torvalds#ifdef __LP64__ 3541da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3551da177e4SLinus Torvalds#endif 3561da177e4SLinus Torvalds bl syscall_trace, %r2 3571da177e4SLinus Torvalds STREG %r28,TASK_PT_GR28(%r1) /* save return value now */ 3581da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3591da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 3601da177e4SLinus Torvalds LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */ 3611da177e4SLinus Torvalds 3621da177e4SLinus Torvalds ldil L%syscall_exit,%r1 3631da177e4SLinus Torvalds be,n R%syscall_exit(%sr7,%r1) 3641da177e4SLinus Torvalds 3651da177e4SLinus Torvalds.Ltrace_rt_sigreturn: 3661da177e4SLinus Torvalds comib,<> 0,%r25,.Ltrace_in_syscall 3671da177e4SLinus Torvalds ldil L%tracesys_sigexit,%r2 3681da177e4SLinus Torvalds be 0(%sr7,%r19) 3691da177e4SLinus Torvalds ldo R%tracesys_sigexit(%r2),%r2 3701da177e4SLinus Torvalds 3711da177e4SLinus Torvaldstracesys_sigexit: 3721da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3731da177e4SLinus Torvalds LDREG 0(%r1), %r1 3741da177e4SLinus Torvalds#ifdef __LP64__ 3751da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3761da177e4SLinus Torvalds#endif 3771da177e4SLinus Torvalds bl syscall_trace, %r2 3781da177e4SLinus Torvalds nop 3791da177e4SLinus Torvalds 3801da177e4SLinus Torvalds ldil L%syscall_exit_rfi,%r1 3811da177e4SLinus Torvalds be,n R%syscall_exit_rfi(%sr7,%r1) 3821da177e4SLinus Torvalds 3831da177e4SLinus Torvalds 3841da177e4SLinus Torvalds /********************************************************* 3851da177e4SLinus Torvalds Light-weight-syscall code 3861da177e4SLinus Torvalds 3871da177e4SLinus Torvalds r20 - lws number 3881da177e4SLinus Torvalds r26,r25,r24,r23,r22 - Input registers 3891da177e4SLinus Torvalds r28 - Function return register 3901da177e4SLinus Torvalds r21 - Error code. 3911da177e4SLinus Torvalds 3921da177e4SLinus Torvalds Scracth: Any of the above that aren't being 3931da177e4SLinus Torvalds currently used, including r1. 3941da177e4SLinus Torvalds 3951da177e4SLinus Torvalds Return pointer: r31 (Not usable) 3961da177e4SLinus Torvalds 3971da177e4SLinus Torvalds Error codes returned by entry path: 3981da177e4SLinus Torvalds 3991da177e4SLinus Torvalds ENOSYS - r20 was an invalid LWS number. 4001da177e4SLinus Torvalds 4011da177e4SLinus Torvalds *********************************************************/ 4021da177e4SLinus Torvaldslws_start: 4031da177e4SLinus Torvalds /* Gate and ensure we return to userspace */ 4041da177e4SLinus Torvalds gate .+8, %r0 4051da177e4SLinus Torvalds depi 3, 31, 2, %r31 /* Ensure we return to userspace */ 4061da177e4SLinus Torvalds 4071da177e4SLinus Torvalds#ifdef __LP64__ 4081da177e4SLinus Torvalds /* FIXME: If we are a 64-bit kernel just 4091da177e4SLinus Torvalds * turn this on unconditionally. 4101da177e4SLinus Torvalds */ 4111da177e4SLinus Torvalds ssm PSW_SM_W, %r1 4121da177e4SLinus Torvalds extrd,u %r1,PSW_W_BIT,1,%r1 4131da177e4SLinus Torvalds /* sp must be aligned on 4, so deposit the W bit setting into 4141da177e4SLinus Torvalds * the bottom of sp temporarily */ 4151da177e4SLinus Torvalds or,ev %r1,%r30,%r30 4161da177e4SLinus Torvalds 4171da177e4SLinus Torvalds /* Clip LWS number to a 32-bit value always */ 4181da177e4SLinus Torvalds depdi 0, 31, 32, %r20 4191da177e4SLinus Torvalds#endif 4201da177e4SLinus Torvalds 4211da177e4SLinus Torvalds /* Is the lws entry number valid? */ 4221da177e4SLinus Torvalds comiclr,>>= __NR_lws_entries, %r20, %r0 4231da177e4SLinus Torvalds b,n lws_exit_nosys 4241da177e4SLinus Torvalds 4251da177e4SLinus Torvalds /* WARNING: Trashing sr2 and sr3 */ 4261da177e4SLinus Torvalds mfsp %sr7,%r1 /* get userspace into sr3 */ 4271da177e4SLinus Torvalds mtsp %r1,%sr3 4281da177e4SLinus Torvalds mtsp %r0,%sr2 /* get kernel space into sr2 */ 4291da177e4SLinus Torvalds 4301da177e4SLinus Torvalds /* Load table start */ 4311da177e4SLinus Torvalds ldil L%lws_table, %r1 4321da177e4SLinus Torvalds ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */ 4331da177e4SLinus Torvalds LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */ 4341da177e4SLinus Torvalds 4351da177e4SLinus Torvalds /* Jump to lws, lws table pointers already relocated */ 4361da177e4SLinus Torvalds be,n 0(%sr2,%r21) 4371da177e4SLinus Torvalds 4381da177e4SLinus Torvaldslws_exit_nosys: 4391da177e4SLinus Torvalds ldo -ENOSYS(%r0),%r21 /* set errno */ 4401da177e4SLinus Torvalds /* Fall through: Return to userspace */ 4411da177e4SLinus Torvalds 4421da177e4SLinus Torvaldslws_exit: 4431da177e4SLinus Torvalds#ifdef __LP64__ 4441da177e4SLinus Torvalds /* decide whether to reset the wide mode bit 4451da177e4SLinus Torvalds * 4461da177e4SLinus Torvalds * For a syscall, the W bit is stored in the lowest bit 4471da177e4SLinus Torvalds * of sp. Extract it and reset W if it is zero */ 4481da177e4SLinus Torvalds extrd,u,*<> %r30,63,1,%r1 4491da177e4SLinus Torvalds rsm PSW_SM_W, %r0 4501da177e4SLinus Torvalds /* now reset the lowest bit of sp if it was set */ 4511da177e4SLinus Torvalds xor %r30,%r1,%r30 4521da177e4SLinus Torvalds#endif 4531da177e4SLinus Torvalds be,n 0(%sr3, %r31) 4541da177e4SLinus Torvalds 4551da177e4SLinus Torvalds 4561da177e4SLinus Torvalds 4571da177e4SLinus Torvalds /*************************************************** 4581da177e4SLinus Torvalds Implementing CAS as an atomic operation: 4591da177e4SLinus Torvalds 4601da177e4SLinus Torvalds %r26 - Address to examine 4611da177e4SLinus Torvalds %r25 - Old value to check (old) 4621da177e4SLinus Torvalds %r24 - New value to set (new) 4631da177e4SLinus Torvalds %r28 - Return prev through this register. 4641da177e4SLinus Torvalds %r21 - Kernel error code 4651da177e4SLinus Torvalds 4661da177e4SLinus Torvalds If debugging is DISabled: 4671da177e4SLinus Torvalds 4681da177e4SLinus Torvalds %r21 has the following meanings: 4691da177e4SLinus Torvalds 4701da177e4SLinus Torvalds EAGAIN - CAS is busy, ldcw failed, try again. 4711da177e4SLinus Torvalds EFAULT - Read or write failed. 4721da177e4SLinus Torvalds 4731da177e4SLinus Torvalds If debugging is enabled: 4741da177e4SLinus Torvalds 4751da177e4SLinus Torvalds EDEADLOCK - CAS called recursively. 4761da177e4SLinus Torvalds EAGAIN && r28 == 1 - CAS is busy. Lock contended. 4771da177e4SLinus Torvalds EAGAIN && r28 == 2 - CAS is busy. ldcw failed. 4781da177e4SLinus Torvalds EFAULT - Read or write failed. 4791da177e4SLinus Torvalds 4801da177e4SLinus Torvalds Scratch: r20, r28, r1 4811da177e4SLinus Torvalds 4821da177e4SLinus Torvalds ****************************************************/ 4831da177e4SLinus Torvalds 4841da177e4SLinus Torvalds /* Do not enable LWS debugging */ 4851da177e4SLinus Torvalds#define ENABLE_LWS_DEBUG 0 4861da177e4SLinus Torvalds 4871da177e4SLinus Torvalds /* ELF64 Process entry path */ 4881da177e4SLinus Torvaldslws_compare_and_swap64: 4891da177e4SLinus Torvalds#ifdef __LP64__ 4901da177e4SLinus Torvalds b,n lws_compare_and_swap 4911da177e4SLinus Torvalds#else 4921da177e4SLinus Torvalds /* If we are not a 64-bit kernel, then we don't 4931da177e4SLinus Torvalds * implement having 64-bit input registers 4941da177e4SLinus Torvalds */ 4951da177e4SLinus Torvalds b,n lws_exit_nosys 4961da177e4SLinus Torvalds#endif 4971da177e4SLinus Torvalds 4981da177e4SLinus Torvalds /* ELF32 Process entry path */ 4991da177e4SLinus Torvaldslws_compare_and_swap32: 5001da177e4SLinus Torvalds#ifdef __LP64__ 5011da177e4SLinus Torvalds /* Clip all the input registers */ 5021da177e4SLinus Torvalds depdi 0, 31, 32, %r26 5031da177e4SLinus Torvalds depdi 0, 31, 32, %r25 5041da177e4SLinus Torvalds depdi 0, 31, 32, %r24 5051da177e4SLinus Torvalds#endif 5061da177e4SLinus Torvalds 5071da177e4SLinus Torvaldslws_compare_and_swap: 5081da177e4SLinus Torvalds#ifdef CONFIG_SMP 5091da177e4SLinus Torvalds /* Load start of lock table */ 5101da177e4SLinus Torvalds ldil L%lws_lock_start, %r20 5111da177e4SLinus Torvalds ldo R%lws_lock_start(%r20), %r28 5121da177e4SLinus Torvalds 5131da177e4SLinus Torvalds /* Extract four bits from r26 and hash lock (Bits 4-7) */ 5141da177e4SLinus Torvalds extru %r26, 27, 4, %r20 5151da177e4SLinus Torvalds 5161da177e4SLinus Torvalds /* Find lock to use, the hash is either one of 0 to 5171da177e4SLinus Torvalds 15, multiplied by 16 (keep it 16-byte aligned) 5181da177e4SLinus Torvalds and add to the lock table offset. */ 5191da177e4SLinus Torvalds shlw %r20, 4, %r20 5201da177e4SLinus Torvalds add %r20, %r28, %r20 5211da177e4SLinus Torvalds 5221da177e4SLinus Torvalds# ifdef ENABLE_LWS_DEBUG 5231da177e4SLinus Torvalds /* 5241da177e4SLinus Torvalds DEBUG, check for deadlock! 5251da177e4SLinus Torvalds If the thread register values are the same 5261da177e4SLinus Torvalds then we were the one that locked it last and 5271da177e4SLinus Torvalds this is a recurisve call that will deadlock. 5281da177e4SLinus Torvalds We *must* giveup this call and fail. 5291da177e4SLinus Torvalds */ 5301da177e4SLinus Torvalds ldw 4(%sr2,%r20), %r28 /* Load thread register */ 5311da177e4SLinus Torvalds mfctl %cr27, %r21 /* Get current thread register */ 5321da177e4SLinus Torvalds cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */ 5331da177e4SLinus Torvalds b lws_exit /* Return error! */ 5341da177e4SLinus Torvalds ldo -EDEADLOCK(%r0), %r21 5351da177e4SLinus Torvaldscas_lock: 5361da177e4SLinus Torvalds cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */ 5371da177e4SLinus Torvalds ldo 1(%r0), %r28 /* 1st case */ 5381da177e4SLinus Torvalds b lws_exit /* Contended... */ 5391da177e4SLinus Torvalds ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 5401da177e4SLinus Torvaldscas_nocontend: 5411da177e4SLinus Torvalds# endif 5421da177e4SLinus Torvalds/* ENABLE_LWS_DEBUG */ 5431da177e4SLinus Torvalds 5441da177e4SLinus Torvalds ldcw 0(%sr2,%r20), %r28 /* Try to acquire the lock */ 5451da177e4SLinus Torvalds cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */ 5461da177e4SLinus Torvaldscas_wouldblock: 5471da177e4SLinus Torvalds ldo 2(%r0), %r28 /* 2nd case */ 5481da177e4SLinus Torvalds b lws_exit /* Contended... */ 5491da177e4SLinus Torvalds ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 5501da177e4SLinus Torvalds#endif 5511da177e4SLinus Torvalds/* CONFIG_SMP */ 5521da177e4SLinus Torvalds 5531da177e4SLinus Torvalds /* 5541da177e4SLinus Torvalds prev = *addr; 5551da177e4SLinus Torvalds if ( prev == old ) 5561da177e4SLinus Torvalds *addr = new; 5571da177e4SLinus Torvalds return prev; 5581da177e4SLinus Torvalds */ 5591da177e4SLinus Torvalds 5601da177e4SLinus Torvalds /* NOTES: 5611da177e4SLinus Torvalds This all works becuse intr_do_signal 5621da177e4SLinus Torvalds and schedule both check the return iasq 5631da177e4SLinus Torvalds and see that we are on the kernel page 5641da177e4SLinus Torvalds so this process is never scheduled off 5651da177e4SLinus Torvalds or is ever sent any signal of any sort, 5661da177e4SLinus Torvalds thus it is wholly atomic from usrspaces 5671da177e4SLinus Torvalds perspective 5681da177e4SLinus Torvalds */ 5691da177e4SLinus Torvaldscas_action: 5701da177e4SLinus Torvalds#if defined CONFIG_SMP && defined ENABLE_LWS_DEBUG 5711da177e4SLinus Torvalds /* DEBUG */ 5721da177e4SLinus Torvalds mfctl %cr27, %r1 5731da177e4SLinus Torvalds stw %r1, 4(%sr2,%r20) 5741da177e4SLinus Torvalds#endif 5751da177e4SLinus Torvalds /* The load and store could fail */ 5761da177e4SLinus Torvalds1: ldw 0(%sr3,%r26), %r28 5771da177e4SLinus Torvalds sub,<> %r28, %r25, %r0 5781da177e4SLinus Torvalds2: stw %r24, 0(%sr3,%r26) 5791da177e4SLinus Torvalds#ifdef CONFIG_SMP 5801da177e4SLinus Torvalds /* Free lock */ 5811da177e4SLinus Torvalds stw %r20, 0(%sr2,%r20) 5821da177e4SLinus Torvalds# ifdef ENABLE_LWS_DEBUG 5831da177e4SLinus Torvalds /* Clear thread register indicator */ 5841da177e4SLinus Torvalds stw %r0, 4(%sr2,%r20) 5851da177e4SLinus Torvalds# endif 5861da177e4SLinus Torvalds#endif 5871da177e4SLinus Torvalds /* Return to userspace, set no error */ 5881da177e4SLinus Torvalds b lws_exit 5891da177e4SLinus Torvalds copy %r0, %r21 5901da177e4SLinus Torvalds 5911da177e4SLinus Torvalds3: 5921da177e4SLinus Torvalds /* Error occured on load or store */ 5931da177e4SLinus Torvalds#ifdef CONFIG_SMP 5941da177e4SLinus Torvalds /* Free lock */ 5951da177e4SLinus Torvalds stw %r20, 0(%sr2,%r20) 5961da177e4SLinus Torvalds# ifdef ENABLE_LWS_DEBUG 5971da177e4SLinus Torvalds stw %r0, 4(%sr2,%r20) 5981da177e4SLinus Torvalds# endif 5991da177e4SLinus Torvalds#endif 6001da177e4SLinus Torvalds b lws_exit 6011da177e4SLinus Torvalds ldo -EFAULT(%r0),%r21 /* set errno */ 6021da177e4SLinus Torvalds nop 6031da177e4SLinus Torvalds nop 6041da177e4SLinus Torvalds nop 6051da177e4SLinus Torvalds nop 6061da177e4SLinus Torvalds 6071da177e4SLinus Torvalds /* Two exception table entries, one for the load, 6081da177e4SLinus Torvalds the other for the store. Either return -EFAULT. 6091da177e4SLinus Torvalds Each of the entries must be relocated. */ 6101da177e4SLinus Torvalds .section __ex_table,"aw" 6111da177e4SLinus Torvalds#ifdef __LP64__ 6121da177e4SLinus Torvalds /* Pad the address calculation */ 6131da177e4SLinus Torvalds .word 0,(2b - linux_gateway_page) 6141da177e4SLinus Torvalds .word 0,(3b - linux_gateway_page) 6151da177e4SLinus Torvalds#else 6161da177e4SLinus Torvalds .word (2b - linux_gateway_page) 6171da177e4SLinus Torvalds .word (3b - linux_gateway_page) 6181da177e4SLinus Torvalds#endif 6191da177e4SLinus Torvalds .previous 6201da177e4SLinus Torvalds 6211da177e4SLinus Torvalds .section __ex_table,"aw" 6221da177e4SLinus Torvalds#ifdef __LP64__ 6231da177e4SLinus Torvalds /* Pad the address calculation */ 6241da177e4SLinus Torvalds .word 0,(1b - linux_gateway_page) 6251da177e4SLinus Torvalds .word 0,(3b - linux_gateway_page) 6261da177e4SLinus Torvalds#else 6271da177e4SLinus Torvalds .word (1b - linux_gateway_page) 6281da177e4SLinus Torvalds .word (3b - linux_gateway_page) 6291da177e4SLinus Torvalds#endif 6301da177e4SLinus Torvalds .previous 6311da177e4SLinus Torvalds 6321da177e4SLinus Torvaldsend_compare_and_swap: 6331da177e4SLinus Torvalds 6341da177e4SLinus Torvalds /* Make sure nothing else is placed on this page */ 6351da177e4SLinus Torvalds .align 4096 6361da177e4SLinus Torvalds .export end_linux_gateway_page 6371da177e4SLinus Torvaldsend_linux_gateway_page: 6381da177e4SLinus Torvalds 6391da177e4SLinus Torvalds /* Relocate symbols assuming linux_gateway_page is mapped 6401da177e4SLinus Torvalds to virtual address 0x0 */ 6411da177e4SLinus Torvalds#ifdef __LP64__ 6421da177e4SLinus Torvalds /* FIXME: The code will always be on the gateay page 6431da177e4SLinus Torvalds and thus it will be on the first 4k, the 6441da177e4SLinus Torvalds assembler seems to think that the final 6451da177e4SLinus Torvalds subtraction result is only a word in 6461da177e4SLinus Torvalds length, so we pad the value. 6471da177e4SLinus Torvalds */ 6481da177e4SLinus Torvalds#define LWS_ENTRY(_name_) .word 0,(lws_##_name_ - linux_gateway_page) 6491da177e4SLinus Torvalds#else 6501da177e4SLinus Torvalds#define LWS_ENTRY(_name_) .word (lws_##_name_ - linux_gateway_page) 6511da177e4SLinus Torvalds#endif 6521da177e4SLinus Torvalds 6531da177e4SLinus Torvalds .align 4096 6541da177e4SLinus Torvalds /* Light-weight-syscall table */ 6551da177e4SLinus Torvalds /* Start of lws table. */ 6561da177e4SLinus Torvalds .export lws_table 6571da177e4SLinus Torvalds.Llws_table: 6581da177e4SLinus Torvaldslws_table: 6591da177e4SLinus Torvalds LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic compare and swap */ 6601da177e4SLinus Torvalds LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic compare and swap */ 6611da177e4SLinus Torvalds /* End of lws table */ 6621da177e4SLinus Torvalds 6631da177e4SLinus Torvalds .align 4096 6641da177e4SLinus Torvalds .export sys_call_table 6651da177e4SLinus Torvalds.Lsys_call_table: 6661da177e4SLinus Torvaldssys_call_table: 6671da177e4SLinus Torvalds#include "syscall_table.S" 6681da177e4SLinus Torvalds 6691da177e4SLinus Torvalds#ifdef __LP64__ 6701da177e4SLinus Torvalds .align 4096 6711da177e4SLinus Torvalds .export sys_call_table64 6721da177e4SLinus Torvalds.Lsys_call_table64: 6731da177e4SLinus Torvaldssys_call_table64: 6741da177e4SLinus Torvalds#define SYSCALL_TABLE_64BIT 6751da177e4SLinus Torvalds#include "syscall_table.S" 6761da177e4SLinus Torvalds#endif 6771da177e4SLinus Torvalds 6781da177e4SLinus Torvalds#ifdef CONFIG_SMP 6791da177e4SLinus Torvalds /* 6801da177e4SLinus Torvalds All light-weight-syscall atomic operations 6811da177e4SLinus Torvalds will use this set of locks 6821da177e4SLinus Torvalds */ 6831da177e4SLinus Torvalds .section .data 6841da177e4SLinus Torvalds .align 4096 6851da177e4SLinus Torvalds .export lws_lock_start 6861da177e4SLinus Torvalds.Llws_lock_start: 6871da177e4SLinus Torvaldslws_lock_start: 6881da177e4SLinus Torvalds /* lws locks */ 6891da177e4SLinus Torvalds .align 16 6901da177e4SLinus Torvalds .rept 16 6911da177e4SLinus Torvalds /* Keep locks aligned at 16-bytes */ 6921da177e4SLinus Torvalds .word 1 6931da177e4SLinus Torvalds .word 0 6941da177e4SLinus Torvalds .word 0 6951da177e4SLinus Torvalds .word 0 6961da177e4SLinus Torvalds .endr 6971da177e4SLinus Torvalds .previous 6981da177e4SLinus Torvalds#endif 6991da177e4SLinus Torvalds/* CONFIG_SMP for lws_lock_start */ 7001da177e4SLinus Torvalds 7011da177e4SLinus Torvalds.end 7021da177e4SLinus Torvalds 7031da177e4SLinus Torvalds 704