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> 131c593571SSam Ravnborg#include <asm/page.h> 141da177e4SLinus Torvalds#include <asm/psw.h> 151da177e4SLinus Torvalds#include <asm/thread_info.h> 161da177e4SLinus Torvalds#include <asm/assembly.h> 171da177e4SLinus Torvalds#include <asm/processor.h> 181da177e4SLinus Torvalds 198e9e9844SHelge Deller#include <linux/linkage.h> 208e9e9844SHelge Deller 211da177e4SLinus Torvalds /* We fill the empty parts of the gateway page with 221da177e4SLinus Torvalds * something that will kill the kernel or a 231da177e4SLinus Torvalds * userspace application. 241da177e4SLinus Torvalds */ 251da177e4SLinus Torvalds#define KILL_INSN break 0,0 261da177e4SLinus Torvalds 270b3d643fSHelge Deller .level LEVEL 288e9e9844SHelge Deller 291da177e4SLinus Torvalds .text 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds .import syscall_exit,code 321da177e4SLinus Torvalds .import syscall_exit_rfi,code 331da177e4SLinus Torvalds 341da177e4SLinus Torvalds /* Linux gateway page is aliased to virtual page 0 in the kernel 351da177e4SLinus Torvalds * address space. Since it is a gateway page it cannot be 361da177e4SLinus Torvalds * dereferenced, so null pointers will still fault. We start 371da177e4SLinus Torvalds * the actual entry point at 0x100. We put break instructions 381da177e4SLinus Torvalds * at the beginning of the page to trap null indirect function 391da177e4SLinus Torvalds * pointers. 401da177e4SLinus Torvalds */ 411da177e4SLinus Torvalds 421c593571SSam Ravnborg .align PAGE_SIZE 438e9e9844SHelge DellerENTRY(linux_gateway_page) 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds /* ADDRESS 0x00 to 0xb0 = 176 bytes / 4 bytes per insn = 44 insns */ 461da177e4SLinus Torvalds .rept 44 471da177e4SLinus Torvalds KILL_INSN 481da177e4SLinus Torvalds .endr 491da177e4SLinus Torvalds 501da177e4SLinus Torvalds /* ADDRESS 0xb0 to 0xb4, lws uses 1 insns for entry */ 511da177e4SLinus Torvalds /* Light-weight-syscall entry must always be located at 0xb0 */ 521da177e4SLinus Torvalds /* WARNING: Keep this number updated with table size changes */ 531da177e4SLinus Torvalds#define __NR_lws_entries (2) 541da177e4SLinus Torvalds 551da177e4SLinus Torvaldslws_entry: 561da177e4SLinus Torvalds /* Unconditional branch to lws_start, located on the 571da177e4SLinus Torvalds same gateway page */ 581da177e4SLinus Torvalds b,n lws_start 591da177e4SLinus Torvalds 601da177e4SLinus Torvalds /* Fill from 0xb4 to 0xe0 */ 611da177e4SLinus Torvalds .rept 11 621da177e4SLinus Torvalds KILL_INSN 631da177e4SLinus Torvalds .endr 641da177e4SLinus Torvalds 651da177e4SLinus Torvalds /* This function MUST be located at 0xe0 for glibc's threading 661da177e4SLinus Torvalds mechanism to work. DO NOT MOVE THIS CODE EVER! */ 671da177e4SLinus Torvaldsset_thread_pointer: 681da177e4SLinus Torvalds gate .+8, %r0 /* increase privilege */ 691da177e4SLinus Torvalds depi 3, 31, 2, %r31 /* Ensure we return into user mode. */ 701da177e4SLinus Torvalds be 0(%sr7,%r31) /* return to user space */ 711da177e4SLinus Torvalds mtctl %r26, %cr27 /* move arg0 to the control register */ 721da177e4SLinus Torvalds 731da177e4SLinus Torvalds /* Increase the chance of trapping if random jumps occur to this 741da177e4SLinus Torvalds address, fill from 0xf0 to 0x100 */ 751da177e4SLinus Torvalds .rept 4 761da177e4SLinus Torvalds KILL_INSN 771da177e4SLinus Torvalds .endr 781da177e4SLinus Torvalds 791da177e4SLinus Torvalds/* This address must remain fixed at 0x100 for glibc's syscalls to work */ 801da177e4SLinus Torvalds .align 256 811da177e4SLinus Torvaldslinux_gateway_entry: 821da177e4SLinus Torvalds gate .+8, %r0 /* become privileged */ 831da177e4SLinus Torvalds mtsp %r0,%sr4 /* get kernel space into sr4 */ 841da177e4SLinus Torvalds mtsp %r0,%sr5 /* get kernel space into sr5 */ 851da177e4SLinus Torvalds mtsp %r0,%sr6 /* get kernel space into sr6 */ 861da177e4SLinus Torvalds mfsp %sr7,%r1 /* save user sr7 */ 871da177e4SLinus Torvalds mtsp %r1,%sr3 /* and store it in sr3 */ 881da177e4SLinus Torvalds 89413059f2SGrant Grundler#ifdef CONFIG_64BIT 901da177e4SLinus Torvalds /* for now we can *always* set the W bit on entry to the syscall 911da177e4SLinus Torvalds * since we don't support wide userland processes. We could 921da177e4SLinus Torvalds * also save the current SM other than in r0 and restore it on 931da177e4SLinus Torvalds * exit from the syscall, and also use that value to know 941da177e4SLinus Torvalds * whether to do narrow or wide syscalls. -PB 951da177e4SLinus Torvalds */ 961da177e4SLinus Torvalds ssm PSW_SM_W, %r1 971da177e4SLinus Torvalds extrd,u %r1,PSW_W_BIT,1,%r1 981da177e4SLinus Torvalds /* sp must be aligned on 4, so deposit the W bit setting into 991da177e4SLinus Torvalds * the bottom of sp temporarily */ 1001da177e4SLinus Torvalds or,ev %r1,%r30,%r30 1011da177e4SLinus Torvalds b,n 1f 1021da177e4SLinus Torvalds /* The top halves of argument registers must be cleared on syscall 1031da177e4SLinus Torvalds * entry from narrow executable. 1041da177e4SLinus Torvalds */ 1051da177e4SLinus Torvalds depdi 0, 31, 32, %r26 1061da177e4SLinus Torvalds depdi 0, 31, 32, %r25 1071da177e4SLinus Torvalds depdi 0, 31, 32, %r24 1081da177e4SLinus Torvalds depdi 0, 31, 32, %r23 1091da177e4SLinus Torvalds depdi 0, 31, 32, %r22 1101da177e4SLinus Torvalds depdi 0, 31, 32, %r21 1111da177e4SLinus Torvalds1: 1121da177e4SLinus Torvalds#endif 1131da177e4SLinus Torvalds mfctl %cr30,%r1 1141da177e4SLinus Torvalds xor %r1,%r30,%r30 /* ye olde xor trick */ 1151da177e4SLinus Torvalds xor %r1,%r30,%r1 1161da177e4SLinus Torvalds xor %r1,%r30,%r30 1171da177e4SLinus Torvalds 1181da177e4SLinus Torvalds ldo THREAD_SZ_ALGN+FRAME_SIZE(%r30),%r30 /* set up kernel stack */ 1191da177e4SLinus Torvalds 1201da177e4SLinus Torvalds /* N.B.: It is critical that we don't set sr7 to 0 until r30 1211da177e4SLinus Torvalds * contains a valid kernel stack pointer. It is also 1221da177e4SLinus Torvalds * critical that we don't start using the kernel stack 1231da177e4SLinus Torvalds * until after sr7 has been set to 0. 1241da177e4SLinus Torvalds */ 1251da177e4SLinus Torvalds 1261da177e4SLinus Torvalds mtsp %r0,%sr7 /* get kernel space into sr7 */ 1271da177e4SLinus Torvalds STREGM %r1,FRAME_SIZE(%r30) /* save r1 (usp) here for now */ 1281da177e4SLinus Torvalds mfctl %cr30,%r1 /* get task ptr in %r1 */ 1291da177e4SLinus Torvalds LDREG TI_TASK(%r1),%r1 1301da177e4SLinus Torvalds 1311da177e4SLinus Torvalds /* Save some registers for sigcontext and potential task 1321da177e4SLinus Torvalds switch (see entry.S for the details of which ones are 1331da177e4SLinus Torvalds saved/restored). TASK_PT_PSW is zeroed so we can see whether 1341da177e4SLinus Torvalds a process is on a syscall or not. For an interrupt the real 1351da177e4SLinus Torvalds PSW value is stored. This is needed for gdb and sys_ptrace. */ 1361da177e4SLinus Torvalds STREG %r0, TASK_PT_PSW(%r1) 1371da177e4SLinus Torvalds STREG %r2, TASK_PT_GR2(%r1) /* preserve rp */ 1381da177e4SLinus Torvalds STREG %r19, TASK_PT_GR19(%r1) 1391da177e4SLinus Torvalds 1401da177e4SLinus Torvalds LDREGM -FRAME_SIZE(%r30), %r2 /* get users sp back */ 141413059f2SGrant Grundler#ifdef CONFIG_64BIT 1421da177e4SLinus Torvalds extrd,u %r2,63,1,%r19 /* W hidden in bottom bit */ 1431da177e4SLinus Torvalds#if 0 1441da177e4SLinus Torvalds xor %r19,%r2,%r2 /* clear bottom bit */ 1451da177e4SLinus Torvalds depd,z %r19,1,1,%r19 1461da177e4SLinus Torvalds std %r19,TASK_PT_PSW(%r1) 1471da177e4SLinus Torvalds#endif 1481da177e4SLinus Torvalds#endif 1491da177e4SLinus Torvalds STREG %r2, TASK_PT_GR30(%r1) /* ... and save it */ 1501da177e4SLinus Torvalds 151aa0eecb0SCarlos O'Donell STREG %r20, TASK_PT_GR20(%r1) /* Syscall number */ 1521da177e4SLinus Torvalds STREG %r21, TASK_PT_GR21(%r1) 1531da177e4SLinus Torvalds STREG %r22, TASK_PT_GR22(%r1) 1541da177e4SLinus Torvalds STREG %r23, TASK_PT_GR23(%r1) /* 4th argument */ 1551da177e4SLinus Torvalds STREG %r24, TASK_PT_GR24(%r1) /* 3rd argument */ 1561da177e4SLinus Torvalds STREG %r25, TASK_PT_GR25(%r1) /* 2nd argument */ 1571da177e4SLinus Torvalds STREG %r26, TASK_PT_GR26(%r1) /* 1st argument */ 1581da177e4SLinus Torvalds STREG %r27, TASK_PT_GR27(%r1) /* user dp */ 1591da177e4SLinus Torvalds STREG %r28, TASK_PT_GR28(%r1) /* return value 0 */ 1601da177e4SLinus Torvalds STREG %r28, TASK_PT_ORIG_R28(%r1) /* return value 0 (saved for signals) */ 1611da177e4SLinus Torvalds STREG %r29, TASK_PT_GR29(%r1) /* return value 1 */ 1621da177e4SLinus Torvalds STREG %r31, TASK_PT_GR31(%r1) /* preserve syscall return ptr */ 1631da177e4SLinus Torvalds 1641da177e4SLinus Torvalds ldo TASK_PT_FR0(%r1), %r27 /* save fpregs from the kernel */ 1651da177e4SLinus Torvalds save_fp %r27 /* or potential task switch */ 1661da177e4SLinus Torvalds 1671da177e4SLinus Torvalds mfctl %cr11, %r27 /* i.e. SAR */ 1681da177e4SLinus Torvalds STREG %r27, TASK_PT_SAR(%r1) 1691da177e4SLinus Torvalds 1701da177e4SLinus Torvalds loadgp 1711da177e4SLinus Torvalds 172413059f2SGrant Grundler#ifdef CONFIG_64BIT 1731da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 1741da177e4SLinus Torvalds copy %r19,%r2 /* W bit back to r2 */ 1751da177e4SLinus Torvalds#else 1761da177e4SLinus Torvalds /* no need to save these on stack in wide mode because the first 8 1771da177e4SLinus Torvalds * args are passed in registers */ 1781da177e4SLinus Torvalds stw %r22, -52(%r30) /* 5th argument */ 1791da177e4SLinus Torvalds stw %r21, -56(%r30) /* 6th argument */ 1801da177e4SLinus Torvalds#endif 1811da177e4SLinus Torvalds 1821da177e4SLinus Torvalds /* Are we being ptraced? */ 1831da177e4SLinus Torvalds mfctl %cr30, %r1 1841da177e4SLinus Torvalds LDREG TI_TASK(%r1),%r1 185376e210bSKyle McMartin ldw TASK_PTRACE(%r1), %r1 1861da177e4SLinus Torvalds bb,<,n %r1,31,.Ltracesys 1871da177e4SLinus Torvalds 1881da177e4SLinus Torvalds /* Note! We cannot use the syscall table that is mapped 1891da177e4SLinus Torvalds nearby since the gateway page is mapped execute-only. */ 1901da177e4SLinus Torvalds 191413059f2SGrant Grundler#ifdef CONFIG_64BIT 1921da177e4SLinus Torvalds ldil L%sys_call_table, %r1 1931da177e4SLinus Torvalds or,= %r2,%r2,%r2 1941da177e4SLinus Torvalds addil L%(sys_call_table64-sys_call_table), %r1 1951da177e4SLinus Torvalds ldo R%sys_call_table(%r1), %r19 1961da177e4SLinus Torvalds or,= %r2,%r2,%r2 1971da177e4SLinus Torvalds ldo R%sys_call_table64(%r1), %r19 1981da177e4SLinus Torvalds#else 1991da177e4SLinus Torvalds ldil L%sys_call_table, %r1 2001da177e4SLinus Torvalds ldo R%sys_call_table(%r1), %r19 2011da177e4SLinus Torvalds#endif 2023bb457afSKyle McMartin comiclr,>> __NR_Linux_syscalls, %r20, %r0 2031da177e4SLinus Torvalds b,n .Lsyscall_nosys 2041da177e4SLinus Torvalds 2051da177e4SLinus Torvalds LDREGX %r20(%r19), %r19 2061da177e4SLinus Torvalds 2071da177e4SLinus Torvalds /* If this is a sys_rt_sigreturn call, and the signal was received 2081da177e4SLinus Torvalds * when not in_syscall, then we want to return via syscall_exit_rfi, 2091da177e4SLinus Torvalds * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 2101da177e4SLinus Torvalds * trampoline code in signal.c). 2111da177e4SLinus Torvalds */ 2121da177e4SLinus Torvalds ldi __NR_rt_sigreturn,%r2 2131da177e4SLinus Torvalds comb,= %r2,%r20,.Lrt_sigreturn 2141da177e4SLinus Torvalds.Lin_syscall: 2151da177e4SLinus Torvalds ldil L%syscall_exit,%r2 2161da177e4SLinus Torvalds be 0(%sr7,%r19) 2171da177e4SLinus Torvalds ldo R%syscall_exit(%r2),%r2 2181da177e4SLinus Torvalds.Lrt_sigreturn: 2191da177e4SLinus Torvalds comib,<> 0,%r25,.Lin_syscall 2201da177e4SLinus Torvalds ldil L%syscall_exit_rfi,%r2 2211da177e4SLinus Torvalds be 0(%sr7,%r19) 2221da177e4SLinus Torvalds ldo R%syscall_exit_rfi(%r2),%r2 2231da177e4SLinus Torvalds 2241da177e4SLinus Torvalds /* Note! Because we are not running where we were linked, any 2251da177e4SLinus Torvalds calls to functions external to this file must be indirect. To 2261da177e4SLinus Torvalds be safe, we apply the opposite rule to functions within this 2271da177e4SLinus Torvalds file, with local labels given to them to ensure correctness. */ 2281da177e4SLinus Torvalds 2291da177e4SLinus Torvalds.Lsyscall_nosys: 2301da177e4SLinus Torvaldssyscall_nosys: 2311da177e4SLinus Torvalds ldil L%syscall_exit,%r1 2321da177e4SLinus Torvalds be R%syscall_exit(%sr7,%r1) 2331da177e4SLinus Torvalds ldo -ENOSYS(%r0),%r28 /* set errno */ 2341da177e4SLinus Torvalds 2351da177e4SLinus Torvalds 2361da177e4SLinus Torvalds/* Warning! This trace code is a virtual duplicate of the code above so be 2371da177e4SLinus Torvalds * sure to maintain both! */ 2381da177e4SLinus Torvalds.Ltracesys: 2391da177e4SLinus Torvaldstracesys: 2401da177e4SLinus Torvalds /* Need to save more registers so the debugger can see where we 2411da177e4SLinus Torvalds * are. This saves only the lower 8 bits of PSW, so that the C 2421da177e4SLinus Torvalds * bit is still clear on syscalls, and the D bit is set if this 2431da177e4SLinus Torvalds * full register save path has been executed. We check the D 2441da177e4SLinus Torvalds * bit on syscall_return_rfi to determine which registers to 2451da177e4SLinus Torvalds * restore. An interrupt results in a full PSW saved with the 2461da177e4SLinus Torvalds * C bit set, a non-straced syscall entry results in C and D clear 2471da177e4SLinus Torvalds * in the saved PSW. 2481da177e4SLinus Torvalds */ 2491da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 2501da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 2511da177e4SLinus Torvalds ssm 0,%r2 2521da177e4SLinus Torvalds STREG %r2,TASK_PT_PSW(%r1) /* Lower 8 bits only!! */ 2531da177e4SLinus Torvalds mfsp %sr0,%r2 2541da177e4SLinus Torvalds STREG %r2,TASK_PT_SR0(%r1) 2551da177e4SLinus Torvalds mfsp %sr1,%r2 2561da177e4SLinus Torvalds STREG %r2,TASK_PT_SR1(%r1) 2571da177e4SLinus Torvalds mfsp %sr2,%r2 2581da177e4SLinus Torvalds STREG %r2,TASK_PT_SR2(%r1) 2591da177e4SLinus Torvalds mfsp %sr3,%r2 2601da177e4SLinus Torvalds STREG %r2,TASK_PT_SR3(%r1) 2611da177e4SLinus Torvalds STREG %r2,TASK_PT_SR4(%r1) 2621da177e4SLinus Torvalds STREG %r2,TASK_PT_SR5(%r1) 2631da177e4SLinus Torvalds STREG %r2,TASK_PT_SR6(%r1) 2641da177e4SLinus Torvalds STREG %r2,TASK_PT_SR7(%r1) 2651da177e4SLinus Torvalds STREG %r2,TASK_PT_IASQ0(%r1) 2661da177e4SLinus Torvalds STREG %r2,TASK_PT_IASQ1(%r1) 2671da177e4SLinus Torvalds LDREG TASK_PT_GR31(%r1),%r2 2681da177e4SLinus Torvalds STREG %r2,TASK_PT_IAOQ0(%r1) 2691da177e4SLinus Torvalds ldo 4(%r2),%r2 2701da177e4SLinus Torvalds STREG %r2,TASK_PT_IAOQ1(%r1) 2711da177e4SLinus Torvalds ldo TASK_REGS(%r1),%r2 2721da177e4SLinus Torvalds /* reg_save %r2 */ 2731da177e4SLinus Torvalds STREG %r3,PT_GR3(%r2) 2741da177e4SLinus Torvalds STREG %r4,PT_GR4(%r2) 2751da177e4SLinus Torvalds STREG %r5,PT_GR5(%r2) 2761da177e4SLinus Torvalds STREG %r6,PT_GR6(%r2) 2771da177e4SLinus Torvalds STREG %r7,PT_GR7(%r2) 2781da177e4SLinus Torvalds STREG %r8,PT_GR8(%r2) 2791da177e4SLinus Torvalds STREG %r9,PT_GR9(%r2) 2801da177e4SLinus Torvalds STREG %r10,PT_GR10(%r2) 2811da177e4SLinus Torvalds STREG %r11,PT_GR11(%r2) 2821da177e4SLinus Torvalds STREG %r12,PT_GR12(%r2) 2831da177e4SLinus Torvalds STREG %r13,PT_GR13(%r2) 2841da177e4SLinus Torvalds STREG %r14,PT_GR14(%r2) 2851da177e4SLinus Torvalds STREG %r15,PT_GR15(%r2) 2861da177e4SLinus Torvalds STREG %r16,PT_GR16(%r2) 2871da177e4SLinus Torvalds STREG %r17,PT_GR17(%r2) 2881da177e4SLinus Torvalds STREG %r18,PT_GR18(%r2) 2891da177e4SLinus Torvalds /* Finished saving things for the debugger */ 2901da177e4SLinus Torvalds 2911da177e4SLinus Torvalds ldil L%syscall_trace,%r1 2921da177e4SLinus Torvalds ldil L%tracesys_next,%r2 2931da177e4SLinus Torvalds be R%syscall_trace(%sr7,%r1) 2941da177e4SLinus Torvalds ldo R%tracesys_next(%r2),%r2 2951da177e4SLinus Torvalds 2961da177e4SLinus Torvaldstracesys_next: 2971da177e4SLinus Torvalds ldil L%sys_call_table,%r1 2981da177e4SLinus Torvalds ldo R%sys_call_table(%r1), %r19 2991da177e4SLinus Torvalds 3001da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3011da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 3021da177e4SLinus Torvalds LDREG TASK_PT_GR20(%r1), %r20 3031da177e4SLinus Torvalds LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */ 3041da177e4SLinus Torvalds LDREG TASK_PT_GR25(%r1), %r25 3051da177e4SLinus Torvalds LDREG TASK_PT_GR24(%r1), %r24 3061da177e4SLinus Torvalds LDREG TASK_PT_GR23(%r1), %r23 307413059f2SGrant Grundler#ifdef CONFIG_64BIT 3081da177e4SLinus Torvalds LDREG TASK_PT_GR22(%r1), %r22 3091da177e4SLinus Torvalds LDREG TASK_PT_GR21(%r1), %r21 3101da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3111da177e4SLinus Torvalds#endif 3121da177e4SLinus Torvalds 3131da177e4SLinus Torvalds comiclr,>>= __NR_Linux_syscalls, %r20, %r0 3141da177e4SLinus Torvalds b,n .Lsyscall_nosys 3151da177e4SLinus Torvalds 3161da177e4SLinus Torvalds LDREGX %r20(%r19), %r19 3171da177e4SLinus Torvalds 3181da177e4SLinus Torvalds /* If this is a sys_rt_sigreturn call, and the signal was received 3191da177e4SLinus Torvalds * when not in_syscall, then we want to return via syscall_exit_rfi, 3201da177e4SLinus Torvalds * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 3211da177e4SLinus Torvalds * trampoline code in signal.c). 3221da177e4SLinus Torvalds */ 3231da177e4SLinus Torvalds ldi __NR_rt_sigreturn,%r2 3241da177e4SLinus Torvalds comb,= %r2,%r20,.Ltrace_rt_sigreturn 3251da177e4SLinus Torvalds.Ltrace_in_syscall: 3261da177e4SLinus Torvalds ldil L%tracesys_exit,%r2 3271da177e4SLinus Torvalds be 0(%sr7,%r19) 3281da177e4SLinus Torvalds ldo R%tracesys_exit(%r2),%r2 3291da177e4SLinus Torvalds 3301da177e4SLinus Torvalds /* Do *not* call this function on the gateway page, because it 3311da177e4SLinus Torvalds makes a direct call to syscall_trace. */ 3321da177e4SLinus Torvalds 3331da177e4SLinus Torvaldstracesys_exit: 3341da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3351da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 336413059f2SGrant Grundler#ifdef CONFIG_64BIT 3371da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3381da177e4SLinus Torvalds#endif 3391da177e4SLinus Torvalds bl syscall_trace, %r2 3401da177e4SLinus Torvalds STREG %r28,TASK_PT_GR28(%r1) /* save return value now */ 3411da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3421da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 3431da177e4SLinus Torvalds LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */ 3441da177e4SLinus Torvalds 3451da177e4SLinus Torvalds ldil L%syscall_exit,%r1 3461da177e4SLinus Torvalds be,n R%syscall_exit(%sr7,%r1) 3471da177e4SLinus Torvalds 3481da177e4SLinus Torvalds.Ltrace_rt_sigreturn: 3491da177e4SLinus Torvalds comib,<> 0,%r25,.Ltrace_in_syscall 3501da177e4SLinus Torvalds ldil L%tracesys_sigexit,%r2 3511da177e4SLinus Torvalds be 0(%sr7,%r19) 3521da177e4SLinus Torvalds ldo R%tracesys_sigexit(%r2),%r2 3531da177e4SLinus Torvalds 3541da177e4SLinus Torvaldstracesys_sigexit: 3551da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3561da177e4SLinus Torvalds LDREG 0(%r1), %r1 357413059f2SGrant Grundler#ifdef CONFIG_64BIT 3581da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3591da177e4SLinus Torvalds#endif 3601da177e4SLinus Torvalds bl syscall_trace, %r2 3611da177e4SLinus Torvalds nop 3621da177e4SLinus Torvalds 3631da177e4SLinus Torvalds ldil L%syscall_exit_rfi,%r1 3641da177e4SLinus Torvalds be,n R%syscall_exit_rfi(%sr7,%r1) 3651da177e4SLinus Torvalds 3661da177e4SLinus Torvalds 3671da177e4SLinus Torvalds /********************************************************* 3681da177e4SLinus Torvalds Light-weight-syscall code 3691da177e4SLinus Torvalds 3701da177e4SLinus Torvalds r20 - lws number 3711da177e4SLinus Torvalds r26,r25,r24,r23,r22 - Input registers 3721da177e4SLinus Torvalds r28 - Function return register 3731da177e4SLinus Torvalds r21 - Error code. 3741da177e4SLinus Torvalds 3751da177e4SLinus Torvalds Scracth: Any of the above that aren't being 3761da177e4SLinus Torvalds currently used, including r1. 3771da177e4SLinus Torvalds 3781da177e4SLinus Torvalds Return pointer: r31 (Not usable) 3791da177e4SLinus Torvalds 3801da177e4SLinus Torvalds Error codes returned by entry path: 3811da177e4SLinus Torvalds 3821da177e4SLinus Torvalds ENOSYS - r20 was an invalid LWS number. 3831da177e4SLinus Torvalds 3841da177e4SLinus Torvalds *********************************************************/ 3851da177e4SLinus Torvaldslws_start: 3861da177e4SLinus Torvalds /* Gate and ensure we return to userspace */ 3871da177e4SLinus Torvalds gate .+8, %r0 3881da177e4SLinus Torvalds depi 3, 31, 2, %r31 /* Ensure we return to userspace */ 3891da177e4SLinus Torvalds 390413059f2SGrant Grundler#ifdef CONFIG_64BIT 3911da177e4SLinus Torvalds /* FIXME: If we are a 64-bit kernel just 3921da177e4SLinus Torvalds * turn this on unconditionally. 3931da177e4SLinus Torvalds */ 3941da177e4SLinus Torvalds ssm PSW_SM_W, %r1 3951da177e4SLinus Torvalds extrd,u %r1,PSW_W_BIT,1,%r1 3961da177e4SLinus Torvalds /* sp must be aligned on 4, so deposit the W bit setting into 3971da177e4SLinus Torvalds * the bottom of sp temporarily */ 3981da177e4SLinus Torvalds or,ev %r1,%r30,%r30 3991da177e4SLinus Torvalds 4001da177e4SLinus Torvalds /* Clip LWS number to a 32-bit value always */ 4011da177e4SLinus Torvalds depdi 0, 31, 32, %r20 4021da177e4SLinus Torvalds#endif 4031da177e4SLinus Torvalds 4041da177e4SLinus Torvalds /* Is the lws entry number valid? */ 4051da177e4SLinus Torvalds comiclr,>>= __NR_lws_entries, %r20, %r0 4061da177e4SLinus Torvalds b,n lws_exit_nosys 4071da177e4SLinus Torvalds 4081da177e4SLinus Torvalds /* WARNING: Trashing sr2 and sr3 */ 4091da177e4SLinus Torvalds mfsp %sr7,%r1 /* get userspace into sr3 */ 4101da177e4SLinus Torvalds mtsp %r1,%sr3 4111da177e4SLinus Torvalds mtsp %r0,%sr2 /* get kernel space into sr2 */ 4121da177e4SLinus Torvalds 4131da177e4SLinus Torvalds /* Load table start */ 4141da177e4SLinus Torvalds ldil L%lws_table, %r1 4151da177e4SLinus Torvalds ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */ 4161da177e4SLinus Torvalds LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */ 4171da177e4SLinus Torvalds 4181da177e4SLinus Torvalds /* Jump to lws, lws table pointers already relocated */ 4191da177e4SLinus Torvalds be,n 0(%sr2,%r21) 4201da177e4SLinus Torvalds 4211da177e4SLinus Torvaldslws_exit_nosys: 4221da177e4SLinus Torvalds ldo -ENOSYS(%r0),%r21 /* set errno */ 4231da177e4SLinus Torvalds /* Fall through: Return to userspace */ 4241da177e4SLinus Torvalds 4251da177e4SLinus Torvaldslws_exit: 426413059f2SGrant Grundler#ifdef CONFIG_64BIT 4271da177e4SLinus Torvalds /* decide whether to reset the wide mode bit 4281da177e4SLinus Torvalds * 4291da177e4SLinus Torvalds * For a syscall, the W bit is stored in the lowest bit 4301da177e4SLinus Torvalds * of sp. Extract it and reset W if it is zero */ 4311da177e4SLinus Torvalds extrd,u,*<> %r30,63,1,%r1 4321da177e4SLinus Torvalds rsm PSW_SM_W, %r0 4331da177e4SLinus Torvalds /* now reset the lowest bit of sp if it was set */ 4341da177e4SLinus Torvalds xor %r30,%r1,%r30 4351da177e4SLinus Torvalds#endif 4361da177e4SLinus Torvalds be,n 0(%sr3, %r31) 4371da177e4SLinus Torvalds 4381da177e4SLinus Torvalds 4391da177e4SLinus Torvalds 4401da177e4SLinus Torvalds /*************************************************** 4411da177e4SLinus Torvalds Implementing CAS as an atomic operation: 4421da177e4SLinus Torvalds 4431da177e4SLinus Torvalds %r26 - Address to examine 4441da177e4SLinus Torvalds %r25 - Old value to check (old) 4451da177e4SLinus Torvalds %r24 - New value to set (new) 4461da177e4SLinus Torvalds %r28 - Return prev through this register. 4471da177e4SLinus Torvalds %r21 - Kernel error code 4481da177e4SLinus Torvalds 4491da177e4SLinus Torvalds If debugging is DISabled: 4501da177e4SLinus Torvalds 4511da177e4SLinus Torvalds %r21 has the following meanings: 4521da177e4SLinus Torvalds 4531da177e4SLinus Torvalds EAGAIN - CAS is busy, ldcw failed, try again. 4541da177e4SLinus Torvalds EFAULT - Read or write failed. 4551da177e4SLinus Torvalds 4561da177e4SLinus Torvalds If debugging is enabled: 4571da177e4SLinus Torvalds 4581da177e4SLinus Torvalds EDEADLOCK - CAS called recursively. 4591da177e4SLinus Torvalds EAGAIN && r28 == 1 - CAS is busy. Lock contended. 4601da177e4SLinus Torvalds EAGAIN && r28 == 2 - CAS is busy. ldcw failed. 4611da177e4SLinus Torvalds EFAULT - Read or write failed. 4621da177e4SLinus Torvalds 4631da177e4SLinus Torvalds Scratch: r20, r28, r1 4641da177e4SLinus Torvalds 4651da177e4SLinus Torvalds ****************************************************/ 4661da177e4SLinus Torvalds 4671da177e4SLinus Torvalds /* Do not enable LWS debugging */ 4681da177e4SLinus Torvalds#define ENABLE_LWS_DEBUG 0 4691da177e4SLinus Torvalds 4701da177e4SLinus Torvalds /* ELF64 Process entry path */ 4711da177e4SLinus Torvaldslws_compare_and_swap64: 472413059f2SGrant Grundler#ifdef CONFIG_64BIT 4731da177e4SLinus Torvalds b,n lws_compare_and_swap 4741da177e4SLinus Torvalds#else 4751da177e4SLinus Torvalds /* If we are not a 64-bit kernel, then we don't 4761da177e4SLinus Torvalds * implement having 64-bit input registers 4771da177e4SLinus Torvalds */ 4781da177e4SLinus Torvalds b,n lws_exit_nosys 4791da177e4SLinus Torvalds#endif 4801da177e4SLinus Torvalds 4811da177e4SLinus Torvalds /* ELF32 Process entry path */ 4821da177e4SLinus Torvaldslws_compare_and_swap32: 483413059f2SGrant Grundler#ifdef CONFIG_64BIT 4841da177e4SLinus Torvalds /* Clip all the input registers */ 4851da177e4SLinus Torvalds depdi 0, 31, 32, %r26 4861da177e4SLinus Torvalds depdi 0, 31, 32, %r25 4871da177e4SLinus Torvalds depdi 0, 31, 32, %r24 4881da177e4SLinus Torvalds#endif 4891da177e4SLinus Torvalds 4901da177e4SLinus Torvaldslws_compare_and_swap: 4911da177e4SLinus Torvalds#ifdef CONFIG_SMP 4921da177e4SLinus Torvalds /* Load start of lock table */ 4931da177e4SLinus Torvalds ldil L%lws_lock_start, %r20 4941da177e4SLinus Torvalds ldo R%lws_lock_start(%r20), %r28 4951da177e4SLinus Torvalds 4961da177e4SLinus Torvalds /* Extract four bits from r26 and hash lock (Bits 4-7) */ 4971da177e4SLinus Torvalds extru %r26, 27, 4, %r20 4981da177e4SLinus Torvalds 4991da177e4SLinus Torvalds /* Find lock to use, the hash is either one of 0 to 5001da177e4SLinus Torvalds 15, multiplied by 16 (keep it 16-byte aligned) 5011da177e4SLinus Torvalds and add to the lock table offset. */ 5021da177e4SLinus Torvalds shlw %r20, 4, %r20 5031da177e4SLinus Torvalds add %r20, %r28, %r20 5041da177e4SLinus Torvalds 505b5e8b733SAurelien Jarno# if ENABLE_LWS_DEBUG 5061da177e4SLinus Torvalds /* 5071da177e4SLinus Torvalds DEBUG, check for deadlock! 5081da177e4SLinus Torvalds If the thread register values are the same 5091da177e4SLinus Torvalds then we were the one that locked it last and 5101da177e4SLinus Torvalds this is a recurisve call that will deadlock. 5111da177e4SLinus Torvalds We *must* giveup this call and fail. 5121da177e4SLinus Torvalds */ 5131da177e4SLinus Torvalds ldw 4(%sr2,%r20), %r28 /* Load thread register */ 514aa0eecb0SCarlos O'Donell /* WARNING: If cr27 cycles to the same value we have problems */ 5151da177e4SLinus Torvalds mfctl %cr27, %r21 /* Get current thread register */ 5161da177e4SLinus Torvalds cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */ 5171da177e4SLinus Torvalds b lws_exit /* Return error! */ 5181da177e4SLinus Torvalds ldo -EDEADLOCK(%r0), %r21 5191da177e4SLinus Torvaldscas_lock: 5201da177e4SLinus Torvalds cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */ 5211da177e4SLinus Torvalds ldo 1(%r0), %r28 /* 1st case */ 5221da177e4SLinus Torvalds b lws_exit /* Contended... */ 5231da177e4SLinus Torvalds ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 5241da177e4SLinus Torvaldscas_nocontend: 5251da177e4SLinus Torvalds# endif 5261da177e4SLinus Torvalds/* ENABLE_LWS_DEBUG */ 5271da177e4SLinus Torvalds 52864f49532SKyle McMartin LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */ 5291da177e4SLinus Torvalds cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */ 5301da177e4SLinus Torvaldscas_wouldblock: 5311da177e4SLinus Torvalds ldo 2(%r0), %r28 /* 2nd case */ 5321da177e4SLinus Torvalds b lws_exit /* Contended... */ 5331da177e4SLinus Torvalds ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 5341da177e4SLinus Torvalds#endif 5351da177e4SLinus Torvalds/* CONFIG_SMP */ 5361da177e4SLinus Torvalds 5371da177e4SLinus Torvalds /* 5381da177e4SLinus Torvalds prev = *addr; 5391da177e4SLinus Torvalds if ( prev == old ) 5401da177e4SLinus Torvalds *addr = new; 5411da177e4SLinus Torvalds return prev; 5421da177e4SLinus Torvalds */ 5431da177e4SLinus Torvalds 5441da177e4SLinus Torvalds /* NOTES: 5451da177e4SLinus Torvalds This all works becuse intr_do_signal 5461da177e4SLinus Torvalds and schedule both check the return iasq 5471da177e4SLinus Torvalds and see that we are on the kernel page 5481da177e4SLinus Torvalds so this process is never scheduled off 5491da177e4SLinus Torvalds or is ever sent any signal of any sort, 5501da177e4SLinus Torvalds thus it is wholly atomic from usrspaces 5511da177e4SLinus Torvalds perspective 5521da177e4SLinus Torvalds */ 5531da177e4SLinus Torvaldscas_action: 554b5e8b733SAurelien Jarno#if defined CONFIG_SMP && ENABLE_LWS_DEBUG 5551da177e4SLinus Torvalds /* DEBUG */ 5561da177e4SLinus Torvalds mfctl %cr27, %r1 5571da177e4SLinus Torvalds stw %r1, 4(%sr2,%r20) 5581da177e4SLinus Torvalds#endif 5591da177e4SLinus Torvalds /* The load and store could fail */ 5601da177e4SLinus Torvalds1: ldw 0(%sr3,%r26), %r28 5611da177e4SLinus Torvalds sub,<> %r28, %r25, %r0 5621da177e4SLinus Torvalds2: stw %r24, 0(%sr3,%r26) 5631da177e4SLinus Torvalds#ifdef CONFIG_SMP 5641da177e4SLinus Torvalds /* Free lock */ 5651da177e4SLinus Torvalds stw %r20, 0(%sr2,%r20) 566b5e8b733SAurelien Jarno# if ENABLE_LWS_DEBUG 5671da177e4SLinus Torvalds /* Clear thread register indicator */ 5681da177e4SLinus Torvalds stw %r0, 4(%sr2,%r20) 5691da177e4SLinus Torvalds# endif 5701da177e4SLinus Torvalds#endif 5711da177e4SLinus Torvalds /* Return to userspace, set no error */ 5721da177e4SLinus Torvalds b lws_exit 5731da177e4SLinus Torvalds copy %r0, %r21 5741da177e4SLinus Torvalds 5751da177e4SLinus Torvalds3: 5761da177e4SLinus Torvalds /* Error occured on load or store */ 5771da177e4SLinus Torvalds#ifdef CONFIG_SMP 5781da177e4SLinus Torvalds /* Free lock */ 5791da177e4SLinus Torvalds stw %r20, 0(%sr2,%r20) 580b5e8b733SAurelien Jarno# if ENABLE_LWS_DEBUG 5811da177e4SLinus Torvalds stw %r0, 4(%sr2,%r20) 5821da177e4SLinus Torvalds# endif 5831da177e4SLinus Torvalds#endif 5841da177e4SLinus Torvalds b lws_exit 5851da177e4SLinus Torvalds ldo -EFAULT(%r0),%r21 /* set errno */ 5861da177e4SLinus Torvalds nop 5871da177e4SLinus Torvalds nop 5881da177e4SLinus Torvalds nop 5891da177e4SLinus Torvalds nop 5901da177e4SLinus Torvalds 5911da177e4SLinus Torvalds /* Two exception table entries, one for the load, 5921da177e4SLinus Torvalds the other for the store. Either return -EFAULT. 5931da177e4SLinus Torvalds Each of the entries must be relocated. */ 5941da177e4SLinus Torvalds .section __ex_table,"aw" 5950b3d643fSHelge Deller ASM_ULONG_INSN (1b - linux_gateway_page), (3b - linux_gateway_page) 5960b3d643fSHelge Deller ASM_ULONG_INSN (2b - linux_gateway_page), (3b - linux_gateway_page) 5971da177e4SLinus Torvalds .previous 5981da177e4SLinus Torvalds 5991da177e4SLinus Torvalds 6001da177e4SLinus Torvalds /* Make sure nothing else is placed on this page */ 6011c593571SSam Ravnborg .align PAGE_SIZE 6028e9e9844SHelge DellerEND(linux_gateway_page) 6038e9e9844SHelge DellerENTRY(end_linux_gateway_page) 6041da177e4SLinus Torvalds 6051da177e4SLinus Torvalds /* Relocate symbols assuming linux_gateway_page is mapped 6061da177e4SLinus Torvalds to virtual address 0x0 */ 6078e9e9844SHelge Deller 6080b3d643fSHelge Deller#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page) 6091da177e4SLinus Torvalds 6101bcdd854SHelge Deller .section .rodata,"a" 6111bcdd854SHelge Deller 6121c593571SSam Ravnborg .align PAGE_SIZE 6131da177e4SLinus Torvalds /* Light-weight-syscall table */ 6141da177e4SLinus Torvalds /* Start of lws table. */ 6158e9e9844SHelge DellerENTRY(lws_table) 6161da177e4SLinus Torvalds LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic compare and swap */ 6171da177e4SLinus Torvalds LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic compare and swap */ 6188e9e9844SHelge DellerEND(lws_table) 6191da177e4SLinus Torvalds /* End of lws table */ 6201da177e4SLinus Torvalds 6211c593571SSam Ravnborg .align PAGE_SIZE 6228e9e9844SHelge DellerENTRY(sys_call_table) 6231da177e4SLinus Torvalds#include "syscall_table.S" 6248e9e9844SHelge DellerEND(sys_call_table) 6251da177e4SLinus Torvalds 626413059f2SGrant Grundler#ifdef CONFIG_64BIT 6271c593571SSam Ravnborg .align PAGE_SIZE 6288e9e9844SHelge DellerENTRY(sys_call_table64) 6291da177e4SLinus Torvalds#define SYSCALL_TABLE_64BIT 6301da177e4SLinus Torvalds#include "syscall_table.S" 6318e9e9844SHelge DellerEND(sys_call_table64) 6321da177e4SLinus Torvalds#endif 6331da177e4SLinus Torvalds 6341da177e4SLinus Torvalds#ifdef CONFIG_SMP 6351da177e4SLinus Torvalds /* 6361da177e4SLinus Torvalds All light-weight-syscall atomic operations 6371da177e4SLinus Torvalds will use this set of locks 6381da177e4SLinus Torvalds */ 6391da177e4SLinus Torvalds .section .data 640873d50e2SKyle McMartin .align PAGE_SIZE 6418e9e9844SHelge DellerENTRY(lws_lock_start) 6421da177e4SLinus Torvalds /* lws locks */ 6431da177e4SLinus Torvalds .align 16 6441da177e4SLinus Torvalds .rept 16 6451da177e4SLinus Torvalds /* Keep locks aligned at 16-bytes */ 6461da177e4SLinus Torvalds .word 1 6471da177e4SLinus Torvalds .word 0 6481da177e4SLinus Torvalds .word 0 6491da177e4SLinus Torvalds .word 0 6501da177e4SLinus Torvalds .endr 6518e9e9844SHelge DellerEND(lws_lock_start) 6521da177e4SLinus Torvalds .previous 6531da177e4SLinus Torvalds#endif 6541da177e4SLinus Torvalds/* CONFIG_SMP for lws_lock_start */ 6551da177e4SLinus Torvalds 6561da177e4SLinus Torvalds.end 6571da177e4SLinus Torvalds 6581da177e4SLinus Torvalds 659