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 100013a854SSam Ravnborg#include <asm/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#include <asm/assembly.h> 161da177e4SLinus Torvalds#include <asm/processor.h> 171da177e4SLinus Torvalds 188e9e9844SHelge Deller#include <linux/linkage.h> 198e9e9844SHelge Deller 201da177e4SLinus Torvalds /* We fill the empty parts of the gateway page with 211da177e4SLinus Torvalds * something that will kill the kernel or a 221da177e4SLinus Torvalds * userspace application. 231da177e4SLinus Torvalds */ 241da177e4SLinus Torvalds#define KILL_INSN break 0,0 251da177e4SLinus Torvalds 260b3d643fSHelge Deller .level LEVEL 278e9e9844SHelge Deller 281da177e4SLinus Torvalds .text 291da177e4SLinus Torvalds 301da177e4SLinus Torvalds .import syscall_exit,code 311da177e4SLinus Torvalds .import syscall_exit_rfi,code 321da177e4SLinus Torvalds 331da177e4SLinus Torvalds /* Linux gateway page is aliased to virtual page 0 in the kernel 341da177e4SLinus Torvalds * address space. Since it is a gateway page it cannot be 351da177e4SLinus Torvalds * dereferenced, so null pointers will still fault. We start 361da177e4SLinus Torvalds * the actual entry point at 0x100. We put break instructions 371da177e4SLinus Torvalds * at the beginning of the page to trap null indirect function 381da177e4SLinus Torvalds * pointers. 391da177e4SLinus Torvalds */ 401da177e4SLinus Torvalds 412fd83038SHelge Deller .align ASM_PAGE_SIZE 428e9e9844SHelge DellerENTRY(linux_gateway_page) 431da177e4SLinus Torvalds 441da177e4SLinus Torvalds /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */ 451da177e4SLinus Torvalds .rept 44 461da177e4SLinus Torvalds KILL_INSN 471da177e4SLinus Torvalds .endr 481da177e4SLinus Torvalds 491da177e4SLinus Torvalds /* ADDRESS 0xb0 to 0xb4, lws uses 1 insns for entry */ 501da177e4SLinus Torvalds /* Light-weight-syscall entry must always be located at 0xb0 */ 511da177e4SLinus Torvalds /* WARNING: Keep this number updated with table size changes */ 521da177e4SLinus Torvalds#define __NR_lws_entries (2) 531da177e4SLinus Torvalds 541da177e4SLinus Torvaldslws_entry: 551da177e4SLinus Torvalds /* Unconditional branch to lws_start, located on the 561da177e4SLinus Torvalds same gateway page */ 571da177e4SLinus Torvalds b,n lws_start 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds /* Fill from 0xb4 to 0xe0 */ 601da177e4SLinus Torvalds .rept 11 611da177e4SLinus Torvalds KILL_INSN 621da177e4SLinus Torvalds .endr 631da177e4SLinus Torvalds 641da177e4SLinus Torvalds /* This function MUST be located at 0xe0 for glibc's threading 651da177e4SLinus Torvalds mechanism to work. DO NOT MOVE THIS CODE EVER! */ 661da177e4SLinus Torvaldsset_thread_pointer: 671da177e4SLinus Torvalds gate .+8, %r0 /* increase privilege */ 681da177e4SLinus Torvalds depi 3, 31, 2, %r31 /* Ensure we return into user mode. */ 691da177e4SLinus Torvalds be 0(%sr7,%r31) /* return to user space */ 701da177e4SLinus Torvalds mtctl %r26, %cr27 /* move arg0 to the control register */ 711da177e4SLinus Torvalds 721da177e4SLinus Torvalds /* Increase the chance of trapping if random jumps occur to this 731da177e4SLinus Torvalds address, fill from 0xf0 to 0x100 */ 741da177e4SLinus Torvalds .rept 4 751da177e4SLinus Torvalds KILL_INSN 761da177e4SLinus Torvalds .endr 771da177e4SLinus Torvalds 781da177e4SLinus Torvalds/* This address must remain fixed at 0x100 for glibc's syscalls to work */ 791da177e4SLinus Torvalds .align 256 801da177e4SLinus Torvaldslinux_gateway_entry: 811da177e4SLinus Torvalds gate .+8, %r0 /* become privileged */ 821da177e4SLinus Torvalds mtsp %r0,%sr4 /* get kernel space into sr4 */ 831da177e4SLinus Torvalds mtsp %r0,%sr5 /* get kernel space into sr5 */ 841da177e4SLinus Torvalds mtsp %r0,%sr6 /* get kernel space into sr6 */ 851da177e4SLinus Torvalds mfsp %sr7,%r1 /* save user sr7 */ 861da177e4SLinus Torvalds mtsp %r1,%sr3 /* and store it in sr3 */ 871da177e4SLinus Torvalds 88413059f2SGrant Grundler#ifdef CONFIG_64BIT 891da177e4SLinus Torvalds /* for now we can *always* set the W bit on entry to the syscall 901da177e4SLinus Torvalds * since we don't support wide userland processes. We could 911da177e4SLinus Torvalds * also save the current SM other than in r0 and restore it on 921da177e4SLinus Torvalds * exit from the syscall, and also use that value to know 931da177e4SLinus Torvalds * whether to do narrow or wide syscalls. -PB 941da177e4SLinus Torvalds */ 951da177e4SLinus Torvalds ssm PSW_SM_W, %r1 961da177e4SLinus Torvalds extrd,u %r1,PSW_W_BIT,1,%r1 971da177e4SLinus Torvalds /* sp must be aligned on 4, so deposit the W bit setting into 981da177e4SLinus Torvalds * the bottom of sp temporarily */ 991da177e4SLinus Torvalds or,ev %r1,%r30,%r30 1001da177e4SLinus Torvalds b,n 1f 1011da177e4SLinus Torvalds /* The top halves of argument registers must be cleared on syscall 1021da177e4SLinus Torvalds * entry from narrow executable. 1031da177e4SLinus Torvalds */ 1041da177e4SLinus Torvalds depdi 0, 31, 32, %r26 1051da177e4SLinus Torvalds depdi 0, 31, 32, %r25 1061da177e4SLinus Torvalds depdi 0, 31, 32, %r24 1071da177e4SLinus Torvalds depdi 0, 31, 32, %r23 1081da177e4SLinus Torvalds depdi 0, 31, 32, %r22 1091da177e4SLinus Torvalds depdi 0, 31, 32, %r21 1101da177e4SLinus Torvalds1: 1111da177e4SLinus Torvalds#endif 1121da177e4SLinus Torvalds mfctl %cr30,%r1 1131da177e4SLinus Torvalds xor %r1,%r30,%r30 /* ye olde xor trick */ 1141da177e4SLinus Torvalds xor %r1,%r30,%r1 1151da177e4SLinus Torvalds xor %r1,%r30,%r30 1161da177e4SLinus Torvalds 1171da177e4SLinus Torvalds ldo THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30 /* set up kernel stack */ 1181da177e4SLinus Torvalds 1191da177e4SLinus Torvalds /* N.B.: It is critical that we don't set sr7 to 0 until r30 1201da177e4SLinus Torvalds * contains a valid kernel stack pointer. It is also 1211da177e4SLinus Torvalds * critical that we don't start using the kernel stack 1221da177e4SLinus Torvalds * until after sr7 has been set to 0. 1231da177e4SLinus Torvalds */ 1241da177e4SLinus Torvalds 1251da177e4SLinus Torvalds mtsp %r0,%sr7 /* get kernel space into sr7 */ 1261da177e4SLinus Torvalds STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */ 1271da177e4SLinus Torvalds mfctl %cr30,%r1 /* get task ptr in %r1 */ 1281da177e4SLinus Torvalds LDREG TI_TASK(%r1),%r1 1291da177e4SLinus Torvalds 1301da177e4SLinus Torvalds /* Save some registers for sigcontext and potential task 1311da177e4SLinus Torvalds switch (see entry.S for the details of which ones are 1321da177e4SLinus Torvalds saved/restored). TASK_PT_PSW is zeroed so we can see whether 1331da177e4SLinus Torvalds a process is on a syscall or not. For an interrupt the real 1341da177e4SLinus Torvalds PSW value is stored. This is needed for gdb and sys_ptrace. */ 1351da177e4SLinus Torvalds STREG %r0, TASK_PT_PSW(%r1) 1361da177e4SLinus Torvalds STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */ 1371da177e4SLinus Torvalds STREG %r19, TASK_PT_GR19(%r1) 1381da177e4SLinus Torvalds 1391da177e4SLinus Torvalds LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */ 140413059f2SGrant Grundler#ifdef CONFIG_64BIT 1411da177e4SLinus Torvalds extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */ 1421da177e4SLinus Torvalds#if 0 1431da177e4SLinus Torvalds xor %r19,%r2,%r2 /* clear bottom bit */ 1441da177e4SLinus Torvalds depd,z %r19,1,1,%r19 1451da177e4SLinus Torvalds std %r19,TASK_PT_PSW(%r1) 1461da177e4SLinus Torvalds#endif 1471da177e4SLinus Torvalds#endif 1481da177e4SLinus Torvalds STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */ 1491da177e4SLinus Torvalds 150aa0eecb0SCarlos O'Donell STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */ 1511da177e4SLinus Torvalds STREG %r21, TASK_PT_GR21(%r1) 1521da177e4SLinus Torvalds STREG %r22, TASK_PT_GR22(%r1) 1531da177e4SLinus Torvalds STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */ 1541da177e4SLinus Torvalds STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */ 1551da177e4SLinus Torvalds STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */ 1561da177e4SLinus Torvalds STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */ 1571da177e4SLinus Torvalds STREG %r27, TASK_PT_GR27(%r1) /* user dp */ 1581da177e4SLinus Torvalds STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */ 1591da177e4SLinus Torvalds STREG %r28, TASK_PT_ORIG_R28(%r1) /* return value 0 (saved for signals) */ 1601da177e4SLinus Torvalds STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */ 1611da177e4SLinus Torvalds STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */ 1621da177e4SLinus Torvalds 1631da177e4SLinus Torvalds ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */ 1641da177e4SLinus Torvalds save_fp %r27 /* or potential task switch */ 1651da177e4SLinus Torvalds 1661da177e4SLinus Torvalds mfctl %cr11, %r27 /* i.e. SAR */ 1671da177e4SLinus Torvalds STREG %r27, TASK_PT_SAR(%r1) 1681da177e4SLinus Torvalds 1691da177e4SLinus Torvalds loadgp 1701da177e4SLinus Torvalds 171413059f2SGrant Grundler#ifdef CONFIG_64BIT 1721da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 1731da177e4SLinus Torvalds copy %r19,%r2 /* W bit back to r2 */ 1741da177e4SLinus Torvalds#else 1751da177e4SLinus Torvalds /* no need to save these on stack in wide mode because the first 8 1761da177e4SLinus Torvalds * args are passed in registers */ 1771da177e4SLinus Torvalds stw %r22, -52(%r30) /* 5th argument */ 1781da177e4SLinus Torvalds stw %r21, -56(%r30) /* 6th argument */ 1791da177e4SLinus Torvalds#endif 1801da177e4SLinus Torvalds 1811da177e4SLinus Torvalds /* Are we being ptraced? */ 1821da177e4SLinus Torvalds mfctl %cr30, %r1 1831da177e4SLinus Torvalds LDREG TI_TASK(%r1),%r1 1841da177e4SLinus Torvalds LDREG TASK_PTRACE(%r1), %r1 1851da177e4SLinus Torvalds bb,<,n %r1,31,.Ltracesys 1861da177e4SLinus Torvalds 1871da177e4SLinus Torvalds /* Note! We cannot use the syscall table that is mapped 1881da177e4SLinus Torvalds nearby since the gateway page is mapped execute-only. */ 1891da177e4SLinus Torvalds 190413059f2SGrant Grundler#ifdef CONFIG_64BIT 1911da177e4SLinus Torvalds ldil L%sys_call_table, %r1 1921da177e4SLinus Torvalds or,= %r2,%r2,%r2 1931da177e4SLinus Torvalds addil L%(sys_call_table64-sys_call_table), %r1 1941da177e4SLinus Torvalds ldo R%sys_call_table(%r1), %r19 1951da177e4SLinus Torvalds or,= %r2,%r2,%r2 1961da177e4SLinus Torvalds ldo R%sys_call_table64(%r1), %r19 1971da177e4SLinus Torvalds#else 1981da177e4SLinus Torvalds ldil L%sys_call_table, %r1 1991da177e4SLinus Torvalds ldo R%sys_call_table(%r1), %r19 2001da177e4SLinus Torvalds#endif 2011da177e4SLinus Torvalds comiclr,>>= __NR_Linux_syscalls, %r20, %r0 2021da177e4SLinus Torvalds b,n .Lsyscall_nosys 2031da177e4SLinus Torvalds 2041da177e4SLinus Torvalds LDREGX %r20(%r19), %r19 2051da177e4SLinus Torvalds 2061da177e4SLinus Torvalds /* If this is a sys_rt_sigreturn call, and the signal was received 2071da177e4SLinus Torvalds * when not in_syscall, then we want to return via syscall_exit_rfi, 2081da177e4SLinus Torvalds * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 2091da177e4SLinus Torvalds * trampoline code in signal.c). 2101da177e4SLinus Torvalds */ 2111da177e4SLinus Torvalds ldi __NR_rt_sigreturn,%r2 2121da177e4SLinus Torvalds comb,= %r2,%r20,.Lrt_sigreturn 2131da177e4SLinus Torvalds.Lin_syscall: 2141da177e4SLinus Torvalds ldil L%syscall_exit,%r2 2151da177e4SLinus Torvalds be 0(%sr7,%r19) 2161da177e4SLinus Torvalds ldo R%syscall_exit(%r2),%r2 2171da177e4SLinus Torvalds.Lrt_sigreturn: 2181da177e4SLinus Torvalds comib,<> 0,%r25,.Lin_syscall 2191da177e4SLinus Torvalds ldil L%syscall_exit_rfi,%r2 2201da177e4SLinus Torvalds be 0(%sr7,%r19) 2211da177e4SLinus Torvalds ldo R%syscall_exit_rfi(%r2),%r2 2221da177e4SLinus Torvalds 2231da177e4SLinus Torvalds /* Note! Because we are not running where we were linked, any 2241da177e4SLinus Torvalds calls to functions external to this file must be indirect. To 2251da177e4SLinus Torvalds be safe, we apply the opposite rule to functions within this 2261da177e4SLinus Torvalds file, with local labels given to them to ensure correctness. */ 2271da177e4SLinus Torvalds 2281da177e4SLinus Torvalds.Lsyscall_nosys: 2291da177e4SLinus Torvaldssyscall_nosys: 2301da177e4SLinus Torvalds ldil L%syscall_exit,%r1 2311da177e4SLinus Torvalds be R%syscall_exit(%sr7,%r1) 2321da177e4SLinus Torvalds ldo -ENOSYS(%r0),%r28 /* set errno */ 2331da177e4SLinus Torvalds 2341da177e4SLinus Torvalds 2351da177e4SLinus Torvalds/* Warning! This trace code is a virtual duplicate of the code above so be 2361da177e4SLinus Torvalds * sure to maintain both! */ 2371da177e4SLinus Torvalds.Ltracesys: 2381da177e4SLinus Torvaldstracesys: 2391da177e4SLinus Torvalds /* Need to save more registers so the debugger can see where we 2401da177e4SLinus Torvalds * are. This saves only the lower 8 bits of PSW, so that the C 2411da177e4SLinus Torvalds * bit is still clear on syscalls, and the D bit is set if this 2421da177e4SLinus Torvalds * full register save path has been executed. We check the D 2431da177e4SLinus Torvalds * bit on syscall_return_rfi to determine which registers to 2441da177e4SLinus Torvalds * restore. An interrupt results in a full PSW saved with the 2451da177e4SLinus Torvalds * C bit set, a non-straced syscall entry results in C and D clear 2461da177e4SLinus Torvalds * in the saved PSW. 2471da177e4SLinus Torvalds */ 2481da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 2491da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 2501da177e4SLinus Torvalds ssm 0,%r2 2511da177e4SLinus Torvalds STREG %r2,TASK_PT_PSW(%r1) /* Lower 8 bits only!! */ 2521da177e4SLinus Torvalds mfsp %sr0,%r2 2531da177e4SLinus Torvalds STREG %r2,TASK_PT_SR0(%r1) 2541da177e4SLinus Torvalds mfsp %sr1,%r2 2551da177e4SLinus Torvalds STREG %r2,TASK_PT_SR1(%r1) 2561da177e4SLinus Torvalds mfsp %sr2,%r2 2571da177e4SLinus Torvalds STREG %r2,TASK_PT_SR2(%r1) 2581da177e4SLinus Torvalds mfsp %sr3,%r2 2591da177e4SLinus Torvalds STREG %r2,TASK_PT_SR3(%r1) 2601da177e4SLinus Torvalds STREG %r2,TASK_PT_SR4(%r1) 2611da177e4SLinus Torvalds STREG %r2,TASK_PT_SR5(%r1) 2621da177e4SLinus Torvalds STREG %r2,TASK_PT_SR6(%r1) 2631da177e4SLinus Torvalds STREG %r2,TASK_PT_SR7(%r1) 2641da177e4SLinus Torvalds STREG %r2,TASK_PT_IASQ0(%r1) 2651da177e4SLinus Torvalds STREG %r2,TASK_PT_IASQ1(%r1) 2661da177e4SLinus Torvalds LDREG TASK_PT_GR31(%r1),%r2 2671da177e4SLinus Torvalds STREG %r2,TASK_PT_IAOQ0(%r1) 2681da177e4SLinus Torvalds ldo 4(%r2),%r2 2691da177e4SLinus Torvalds STREG %r2,TASK_PT_IAOQ1(%r1) 2701da177e4SLinus Torvalds ldo TASK_REGS(%r1),%r2 2711da177e4SLinus Torvalds /* reg_save %r2 */ 2721da177e4SLinus Torvalds STREG %r3,PT_GR3(%r2) 2731da177e4SLinus Torvalds STREG %r4,PT_GR4(%r2) 2741da177e4SLinus Torvalds STREG %r5,PT_GR5(%r2) 2751da177e4SLinus Torvalds STREG %r6,PT_GR6(%r2) 2761da177e4SLinus Torvalds STREG %r7,PT_GR7(%r2) 2771da177e4SLinus Torvalds STREG %r8,PT_GR8(%r2) 2781da177e4SLinus Torvalds STREG %r9,PT_GR9(%r2) 2791da177e4SLinus Torvalds STREG %r10,PT_GR10(%r2) 2801da177e4SLinus Torvalds STREG %r11,PT_GR11(%r2) 2811da177e4SLinus Torvalds STREG %r12,PT_GR12(%r2) 2821da177e4SLinus Torvalds STREG %r13,PT_GR13(%r2) 2831da177e4SLinus Torvalds STREG %r14,PT_GR14(%r2) 2841da177e4SLinus Torvalds STREG %r15,PT_GR15(%r2) 2851da177e4SLinus Torvalds STREG %r16,PT_GR16(%r2) 2861da177e4SLinus Torvalds STREG %r17,PT_GR17(%r2) 2871da177e4SLinus Torvalds STREG %r18,PT_GR18(%r2) 2881da177e4SLinus Torvalds /* Finished saving things for the debugger */ 2891da177e4SLinus Torvalds 2901da177e4SLinus Torvalds ldil L%syscall_trace,%r1 2911da177e4SLinus Torvalds ldil L%tracesys_next,%r2 2921da177e4SLinus Torvalds be R%syscall_trace(%sr7,%r1) 2931da177e4SLinus Torvalds ldo R%tracesys_next(%r2),%r2 2941da177e4SLinus Torvalds 2951da177e4SLinus Torvaldstracesys_next: 2961da177e4SLinus Torvalds ldil L%sys_call_table,%r1 2971da177e4SLinus Torvalds ldo R%sys_call_table(%r1), %r19 2981da177e4SLinus Torvalds 2991da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3001da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 3011da177e4SLinus Torvalds LDREG TASK_PT_GR20(%r1), %r20 3021da177e4SLinus Torvalds LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */ 3031da177e4SLinus Torvalds LDREG TASK_PT_GR25(%r1), %r25 3041da177e4SLinus Torvalds LDREG TASK_PT_GR24(%r1), %r24 3051da177e4SLinus Torvalds LDREG TASK_PT_GR23(%r1), %r23 306413059f2SGrant Grundler#ifdef CONFIG_64BIT 3071da177e4SLinus Torvalds LDREG TASK_PT_GR22(%r1), %r22 3081da177e4SLinus Torvalds LDREG TASK_PT_GR21(%r1), %r21 3091da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3101da177e4SLinus Torvalds#endif 3111da177e4SLinus Torvalds 3121da177e4SLinus Torvalds comiclr,>>= __NR_Linux_syscalls, %r20, %r0 3131da177e4SLinus Torvalds b,n .Lsyscall_nosys 3141da177e4SLinus Torvalds 3151da177e4SLinus Torvalds LDREGX %r20(%r19), %r19 3161da177e4SLinus Torvalds 3171da177e4SLinus Torvalds /* If this is a sys_rt_sigreturn call, and the signal was received 3181da177e4SLinus Torvalds * when not in_syscall, then we want to return via syscall_exit_rfi, 3191da177e4SLinus Torvalds * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 3201da177e4SLinus Torvalds * trampoline code in signal.c). 3211da177e4SLinus Torvalds */ 3221da177e4SLinus Torvalds ldi __NR_rt_sigreturn,%r2 3231da177e4SLinus Torvalds comb,= %r2,%r20,.Ltrace_rt_sigreturn 3241da177e4SLinus Torvalds.Ltrace_in_syscall: 3251da177e4SLinus Torvalds ldil L%tracesys_exit,%r2 3261da177e4SLinus Torvalds be 0(%sr7,%r19) 3271da177e4SLinus Torvalds ldo R%tracesys_exit(%r2),%r2 3281da177e4SLinus Torvalds 3291da177e4SLinus Torvalds /* Do *not* call this function on the gateway page, because it 3301da177e4SLinus Torvalds makes a direct call to syscall_trace. */ 3311da177e4SLinus Torvalds 3321da177e4SLinus Torvaldstracesys_exit: 3331da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3341da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 335413059f2SGrant Grundler#ifdef CONFIG_64BIT 3361da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3371da177e4SLinus Torvalds#endif 3381da177e4SLinus Torvalds bl syscall_trace, %r2 3391da177e4SLinus Torvalds STREG %r28,TASK_PT_GR28(%r1) /* save return value now */ 3401da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3411da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 3421da177e4SLinus Torvalds LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */ 3431da177e4SLinus Torvalds 3441da177e4SLinus Torvalds ldil L%syscall_exit,%r1 3451da177e4SLinus Torvalds be,n R%syscall_exit(%sr7,%r1) 3461da177e4SLinus Torvalds 3471da177e4SLinus Torvalds.Ltrace_rt_sigreturn: 3481da177e4SLinus Torvalds comib,<> 0,%r25,.Ltrace_in_syscall 3491da177e4SLinus Torvalds ldil L%tracesys_sigexit,%r2 3501da177e4SLinus Torvalds be 0(%sr7,%r19) 3511da177e4SLinus Torvalds ldo R%tracesys_sigexit(%r2),%r2 3521da177e4SLinus Torvalds 3531da177e4SLinus Torvaldstracesys_sigexit: 3541da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3551da177e4SLinus Torvalds LDREG 0(%r1), %r1 356413059f2SGrant Grundler#ifdef CONFIG_64BIT 3571da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3581da177e4SLinus Torvalds#endif 3591da177e4SLinus Torvalds bl syscall_trace, %r2 3601da177e4SLinus Torvalds nop 3611da177e4SLinus Torvalds 3621da177e4SLinus Torvalds ldil L%syscall_exit_rfi,%r1 3631da177e4SLinus Torvalds be,n R%syscall_exit_rfi(%sr7,%r1) 3641da177e4SLinus Torvalds 3651da177e4SLinus Torvalds 3661da177e4SLinus Torvalds /********************************************************* 3671da177e4SLinus Torvalds Light-weight-syscall code 3681da177e4SLinus Torvalds 3691da177e4SLinus Torvalds r20 - lws number 3701da177e4SLinus Torvalds r26,r25,r24,r23,r22 - Input registers 3711da177e4SLinus Torvalds r28 - Function return register 3721da177e4SLinus Torvalds r21 - Error code. 3731da177e4SLinus Torvalds 3741da177e4SLinus Torvalds Scracth: Any of the above that aren't being 3751da177e4SLinus Torvalds currently used, including r1. 3761da177e4SLinus Torvalds 3771da177e4SLinus Torvalds Return pointer: r31 (Not usable) 3781da177e4SLinus Torvalds 3791da177e4SLinus Torvalds Error codes returned by entry path: 3801da177e4SLinus Torvalds 3811da177e4SLinus Torvalds ENOSYS - r20 was an invalid LWS number. 3821da177e4SLinus Torvalds 3831da177e4SLinus Torvalds *********************************************************/ 3841da177e4SLinus Torvaldslws_start: 3851da177e4SLinus Torvalds /* Gate and ensure we return to userspace */ 3861da177e4SLinus Torvalds gate .+8, %r0 3871da177e4SLinus Torvalds depi 3, 31, 2, %r31 /* Ensure we return to userspace */ 3881da177e4SLinus Torvalds 389413059f2SGrant Grundler#ifdef CONFIG_64BIT 3901da177e4SLinus Torvalds /* FIXME: If we are a 64-bit kernel just 3911da177e4SLinus Torvalds * turn this on unconditionally. 3921da177e4SLinus Torvalds */ 3931da177e4SLinus Torvalds ssm PSW_SM_W, %r1 3941da177e4SLinus Torvalds extrd,u %r1,PSW_W_BIT,1,%r1 3951da177e4SLinus Torvalds /* sp must be aligned on 4, so deposit the W bit setting into 3961da177e4SLinus Torvalds * the bottom of sp temporarily */ 3971da177e4SLinus Torvalds or,ev %r1,%r30,%r30 3981da177e4SLinus Torvalds 3991da177e4SLinus Torvalds /* Clip LWS number to a 32-bit value always */ 4001da177e4SLinus Torvalds depdi 0, 31, 32, %r20 4011da177e4SLinus Torvalds#endif 4021da177e4SLinus Torvalds 4031da177e4SLinus Torvalds /* Is the lws entry number valid? */ 4041da177e4SLinus Torvalds comiclr,>>= __NR_lws_entries, %r20, %r0 4051da177e4SLinus Torvalds b,n lws_exit_nosys 4061da177e4SLinus Torvalds 4071da177e4SLinus Torvalds /* WARNING: Trashing sr2 and sr3 */ 4081da177e4SLinus Torvalds mfsp %sr7,%r1 /* get userspace into sr3 */ 4091da177e4SLinus Torvalds mtsp %r1,%sr3 4101da177e4SLinus Torvalds mtsp %r0,%sr2 /* get kernel space into sr2 */ 4111da177e4SLinus Torvalds 4121da177e4SLinus Torvalds /* Load table start */ 4131da177e4SLinus Torvalds ldil L%lws_table, %r1 4141da177e4SLinus Torvalds ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */ 4151da177e4SLinus Torvalds LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */ 4161da177e4SLinus Torvalds 4171da177e4SLinus Torvalds /* Jump to lws, lws table pointers already relocated */ 4181da177e4SLinus Torvalds be,n 0(%sr2,%r21) 4191da177e4SLinus Torvalds 4201da177e4SLinus Torvaldslws_exit_nosys: 4211da177e4SLinus Torvalds ldo -ENOSYS(%r0),%r21 /* set errno */ 4221da177e4SLinus Torvalds /* Fall through: Return to userspace */ 4231da177e4SLinus Torvalds 4241da177e4SLinus Torvaldslws_exit: 425413059f2SGrant Grundler#ifdef CONFIG_64BIT 4261da177e4SLinus Torvalds /* decide whether to reset the wide mode bit 4271da177e4SLinus Torvalds * 4281da177e4SLinus Torvalds * For a syscall, the W bit is stored in the lowest bit 4291da177e4SLinus Torvalds * of sp. Extract it and reset W if it is zero */ 4301da177e4SLinus Torvalds extrd,u,*<> %r30,63,1,%r1 4311da177e4SLinus Torvalds rsm PSW_SM_W, %r0 4321da177e4SLinus Torvalds /* now reset the lowest bit of sp if it was set */ 4331da177e4SLinus Torvalds xor %r30,%r1,%r30 4341da177e4SLinus Torvalds#endif 4351da177e4SLinus Torvalds be,n 0(%sr3, %r31) 4361da177e4SLinus Torvalds 4371da177e4SLinus Torvalds 4381da177e4SLinus Torvalds 4391da177e4SLinus Torvalds /*************************************************** 4401da177e4SLinus Torvalds Implementing CAS as an atomic operation: 4411da177e4SLinus Torvalds 4421da177e4SLinus Torvalds %r26 - Address to examine 4431da177e4SLinus Torvalds %r25 - Old value to check (old) 4441da177e4SLinus Torvalds %r24 - New value to set (new) 4451da177e4SLinus Torvalds %r28 - Return prev through this register. 4461da177e4SLinus Torvalds %r21 - Kernel error code 4471da177e4SLinus Torvalds 4481da177e4SLinus Torvalds If debugging is DISabled: 4491da177e4SLinus Torvalds 4501da177e4SLinus Torvalds %r21 has the following meanings: 4511da177e4SLinus Torvalds 4521da177e4SLinus Torvalds EAGAIN - CAS is busy, ldcw failed, try again. 4531da177e4SLinus Torvalds EFAULT - Read or write failed. 4541da177e4SLinus Torvalds 4551da177e4SLinus Torvalds If debugging is enabled: 4561da177e4SLinus Torvalds 4571da177e4SLinus Torvalds EDEADLOCK - CAS called recursively. 4581da177e4SLinus Torvalds EAGAIN && r28 == 1 - CAS is busy. Lock contended. 4591da177e4SLinus Torvalds EAGAIN && r28 == 2 - CAS is busy. ldcw failed. 4601da177e4SLinus Torvalds EFAULT - Read or write failed. 4611da177e4SLinus Torvalds 4621da177e4SLinus Torvalds Scratch: r20, r28, r1 4631da177e4SLinus Torvalds 4641da177e4SLinus Torvalds ****************************************************/ 4651da177e4SLinus Torvalds 4661da177e4SLinus Torvalds /* Do not enable LWS debugging */ 4671da177e4SLinus Torvalds#define ENABLE_LWS_DEBUG 0 4681da177e4SLinus Torvalds 4691da177e4SLinus Torvalds /* ELF64 Process entry path */ 4701da177e4SLinus Torvaldslws_compare_and_swap64: 471413059f2SGrant Grundler#ifdef CONFIG_64BIT 4721da177e4SLinus Torvalds b,n lws_compare_and_swap 4731da177e4SLinus Torvalds#else 4741da177e4SLinus Torvalds /* If we are not a 64-bit kernel, then we don't 4751da177e4SLinus Torvalds * implement having 64-bit input registers 4761da177e4SLinus Torvalds */ 4771da177e4SLinus Torvalds b,n lws_exit_nosys 4781da177e4SLinus Torvalds#endif 4791da177e4SLinus Torvalds 4801da177e4SLinus Torvalds /* ELF32 Process entry path */ 4811da177e4SLinus Torvaldslws_compare_and_swap32: 482413059f2SGrant Grundler#ifdef CONFIG_64BIT 4831da177e4SLinus Torvalds /* Clip all the input registers */ 4841da177e4SLinus Torvalds depdi 0, 31, 32, %r26 4851da177e4SLinus Torvalds depdi 0, 31, 32, %r25 4861da177e4SLinus Torvalds depdi 0, 31, 32, %r24 4871da177e4SLinus Torvalds#endif 4881da177e4SLinus Torvalds 4891da177e4SLinus Torvaldslws_compare_and_swap: 4901da177e4SLinus Torvalds#ifdef CONFIG_SMP 4911da177e4SLinus Torvalds /* Load start of lock table */ 4921da177e4SLinus Torvalds ldil L%lws_lock_start, %r20 4931da177e4SLinus Torvalds ldo R%lws_lock_start(%r20), %r28 4941da177e4SLinus Torvalds 4951da177e4SLinus Torvalds /* Extract four bits from r26 and hash lock (Bits 4-7) */ 4961da177e4SLinus Torvalds extru %r26, 27, 4, %r20 4971da177e4SLinus Torvalds 4981da177e4SLinus Torvalds /* Find lock to use, the hash is either one of 0 to 4991da177e4SLinus Torvalds 15, multiplied by 16 (keep it 16-byte aligned) 5001da177e4SLinus Torvalds and add to the lock table offset. */ 5011da177e4SLinus Torvalds shlw %r20, 4, %r20 5021da177e4SLinus Torvalds add %r20, %r28, %r20 5031da177e4SLinus Torvalds 504b5e8b733SAurelien Jarno# if ENABLE_LWS_DEBUG 5051da177e4SLinus Torvalds /* 5061da177e4SLinus Torvalds DEBUG, check for deadlock! 5071da177e4SLinus Torvalds If the thread register values are the same 5081da177e4SLinus Torvalds then we were the one that locked it last and 5091da177e4SLinus Torvalds this is a recurisve call that will deadlock. 5101da177e4SLinus Torvalds We *must* giveup this call and fail. 5111da177e4SLinus Torvalds */ 5121da177e4SLinus Torvalds ldw 4(%sr2,%r20), %r28 /* Load thread register */ 513aa0eecb0SCarlos O'Donell /* WARNING: If cr27 cycles to the same value we have problems */ 5141da177e4SLinus Torvalds mfctl %cr27, %r21 /* Get current thread register */ 5151da177e4SLinus Torvalds cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */ 5161da177e4SLinus Torvalds b lws_exit /* Return error! */ 5171da177e4SLinus Torvalds ldo -EDEADLOCK(%r0), %r21 5181da177e4SLinus Torvaldscas_lock: 5191da177e4SLinus Torvalds cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */ 5201da177e4SLinus Torvalds ldo 1(%r0), %r28 /* 1st case */ 5211da177e4SLinus Torvalds b lws_exit /* Contended... */ 5221da177e4SLinus Torvalds ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 5231da177e4SLinus Torvaldscas_nocontend: 5241da177e4SLinus Torvalds# endif 5251da177e4SLinus Torvalds/* ENABLE_LWS_DEBUG */ 5261da177e4SLinus Torvalds 52764f49532SKyle McMartin LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */ 5281da177e4SLinus Torvalds cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */ 5291da177e4SLinus Torvaldscas_wouldblock: 5301da177e4SLinus Torvalds ldo 2(%r0), %r28 /* 2nd case */ 5311da177e4SLinus Torvalds b lws_exit /* Contended... */ 5321da177e4SLinus Torvalds ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 5331da177e4SLinus Torvalds#endif 5341da177e4SLinus Torvalds/* CONFIG_SMP */ 5351da177e4SLinus Torvalds 5361da177e4SLinus Torvalds /* 5371da177e4SLinus Torvalds prev = *addr; 5381da177e4SLinus Torvalds if ( prev == old ) 5391da177e4SLinus Torvalds *addr = new; 5401da177e4SLinus Torvalds return prev; 5411da177e4SLinus Torvalds */ 5421da177e4SLinus Torvalds 5431da177e4SLinus Torvalds /* NOTES: 5441da177e4SLinus Torvalds This all works becuse intr_do_signal 5451da177e4SLinus Torvalds and schedule both check the return iasq 5461da177e4SLinus Torvalds and see that we are on the kernel page 5471da177e4SLinus Torvalds so this process is never scheduled off 5481da177e4SLinus Torvalds or is ever sent any signal of any sort, 5491da177e4SLinus Torvalds thus it is wholly atomic from usrspaces 5501da177e4SLinus Torvalds perspective 5511da177e4SLinus Torvalds */ 5521da177e4SLinus Torvaldscas_action: 553b5e8b733SAurelien Jarno#if defined CONFIG_SMP && ENABLE_LWS_DEBUG 5541da177e4SLinus Torvalds /* DEBUG */ 5551da177e4SLinus Torvalds mfctl %cr27, %r1 5561da177e4SLinus Torvalds stw %r1, 4(%sr2,%r20) 5571da177e4SLinus Torvalds#endif 5581da177e4SLinus Torvalds /* The load and store could fail */ 5591da177e4SLinus Torvalds1: ldw 0(%sr3,%r26), %r28 5601da177e4SLinus Torvalds sub,<> %r28, %r25, %r0 5611da177e4SLinus Torvalds2: stw %r24, 0(%sr3,%r26) 5621da177e4SLinus Torvalds#ifdef CONFIG_SMP 5631da177e4SLinus Torvalds /* Free lock */ 5641da177e4SLinus Torvalds stw %r20, 0(%sr2,%r20) 565b5e8b733SAurelien Jarno# if ENABLE_LWS_DEBUG 5661da177e4SLinus Torvalds /* Clear thread register indicator */ 5671da177e4SLinus Torvalds stw %r0, 4(%sr2,%r20) 5681da177e4SLinus Torvalds# endif 5691da177e4SLinus Torvalds#endif 5701da177e4SLinus Torvalds /* Return to userspace, set no error */ 5711da177e4SLinus Torvalds b lws_exit 5721da177e4SLinus Torvalds copy %r0, %r21 5731da177e4SLinus Torvalds 5741da177e4SLinus Torvalds3: 5751da177e4SLinus Torvalds /* Error occured on load or store */ 5761da177e4SLinus Torvalds#ifdef CONFIG_SMP 5771da177e4SLinus Torvalds /* Free lock */ 5781da177e4SLinus Torvalds stw %r20, 0(%sr2,%r20) 579b5e8b733SAurelien Jarno# if ENABLE_LWS_DEBUG 5801da177e4SLinus Torvalds stw %r0, 4(%sr2,%r20) 5811da177e4SLinus Torvalds# endif 5821da177e4SLinus Torvalds#endif 5831da177e4SLinus Torvalds b lws_exit 5841da177e4SLinus Torvalds ldo -EFAULT(%r0),%r21 /* set errno */ 5851da177e4SLinus Torvalds nop 5861da177e4SLinus Torvalds nop 5871da177e4SLinus Torvalds nop 5881da177e4SLinus Torvalds nop 5891da177e4SLinus Torvalds 5901da177e4SLinus Torvalds /* Two exception table entries, one for the load, 5911da177e4SLinus Torvalds the other for the store. Either return -EFAULT. 5921da177e4SLinus Torvalds Each of the entries must be relocated. */ 5931da177e4SLinus Torvalds .section __ex_table,"aw" 5940b3d643fSHelge Deller ASM_ULONG_INSN (1b - linux_gateway_page), (3b - linux_gateway_page) 5950b3d643fSHelge Deller ASM_ULONG_INSN (2b - linux_gateway_page), (3b - linux_gateway_page) 5961da177e4SLinus Torvalds .previous 5971da177e4SLinus Torvalds 5981da177e4SLinus Torvalds 5991da177e4SLinus Torvalds /* Make sure nothing else is placed on this page */ 6002fd83038SHelge Deller .align ASM_PAGE_SIZE 6018e9e9844SHelge DellerEND(linux_gateway_page) 6028e9e9844SHelge DellerENTRY(end_linux_gateway_page) 6031da177e4SLinus Torvalds 6041da177e4SLinus Torvalds /* Relocate symbols assuming linux_gateway_page is mapped 6051da177e4SLinus Torvalds to virtual address 0x0 */ 6068e9e9844SHelge Deller 6070b3d643fSHelge Deller#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page) 6081da177e4SLinus Torvalds 6091bcdd854SHelge Deller .section .rodata,"a" 6101bcdd854SHelge Deller 6112fd83038SHelge Deller .align ASM_PAGE_SIZE 6121da177e4SLinus Torvalds /* Light-weight-syscall table */ 6131da177e4SLinus Torvalds /* Start of lws table. */ 6148e9e9844SHelge DellerENTRY(lws_table) 6151da177e4SLinus Torvalds LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic compare and swap */ 6161da177e4SLinus Torvalds LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic compare and swap */ 6178e9e9844SHelge DellerEND(lws_table) 6181da177e4SLinus Torvalds /* End of lws table */ 6191da177e4SLinus Torvalds 6202fd83038SHelge Deller .align ASM_PAGE_SIZE 6218e9e9844SHelge DellerENTRY(sys_call_table) 6221da177e4SLinus Torvalds#include "syscall_table.S" 6238e9e9844SHelge DellerEND(sys_call_table) 6241da177e4SLinus Torvalds 625413059f2SGrant Grundler#ifdef CONFIG_64BIT 6262fd83038SHelge Deller .align ASM_PAGE_SIZE 6278e9e9844SHelge DellerENTRY(sys_call_table64) 6281da177e4SLinus Torvalds#define SYSCALL_TABLE_64BIT 6291da177e4SLinus Torvalds#include "syscall_table.S" 6308e9e9844SHelge DellerEND(sys_call_table64) 6311da177e4SLinus Torvalds#endif 6321da177e4SLinus Torvalds 6331da177e4SLinus Torvalds#ifdef CONFIG_SMP 6341da177e4SLinus Torvalds /* 6351da177e4SLinus Torvalds All light-weight-syscall atomic operations 6361da177e4SLinus Torvalds will use this set of locks 6371da177e4SLinus Torvalds */ 6381da177e4SLinus Torvalds .section .data 6391da177e4SLinus Torvalds .align 4096 6408e9e9844SHelge DellerENTRY(lws_lock_start) 6411da177e4SLinus Torvalds /* lws locks */ 6421da177e4SLinus Torvalds .align 16 6431da177e4SLinus Torvalds .rept 16 6441da177e4SLinus Torvalds /* Keep locks aligned at 16-bytes */ 6451da177e4SLinus Torvalds .word 1 6461da177e4SLinus Torvalds .word 0 6471da177e4SLinus Torvalds .word 0 6481da177e4SLinus Torvalds .word 0 6491da177e4SLinus Torvalds .endr 6508e9e9844SHelge DellerEND(lws_lock_start) 6511da177e4SLinus Torvalds .previous 6521da177e4SLinus Torvalds#endif 6531da177e4SLinus Torvalds/* CONFIG_SMP for lws_lock_start */ 6541da177e4SLinus Torvalds 6551da177e4SLinus Torvalds.end 6561da177e4SLinus Torvalds 6571da177e4SLinus Torvalds 658