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 29dfcf753bSKyle McMartin .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 50f4c0346cSJohn David Anglin /* ADDRESS 0xb0 to 0xb8, lws uses two 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: 56f4c0346cSJohn David Anglin gate lws_start, %r0 /* increase privilege */ 57f4c0346cSJohn David Anglin depi 3, 31, 2, %r31 /* Ensure we return into user mode. */ 581da177e4SLinus Torvalds 59f4c0346cSJohn David Anglin /* Fill from 0xb8 to 0xe0 */ 60f4c0346cSJohn David Anglin .rept 10 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 */ 15900df111eSAl Viro STREG %r0, TASK_PT_ORIG_R28(%r1) /* don't prohibit restarts */ 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 184376e210bSKyle McMartin ldw 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 2013bb457afSKyle McMartin 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 2902798af1aSKyle McMartin copy %r2,%r26 2912798af1aSKyle McMartin ldil L%do_syscall_trace_enter,%r1 2921da177e4SLinus Torvalds ldil L%tracesys_next,%r2 2932798af1aSKyle McMartin be R%do_syscall_trace_enter(%sr7,%r1) 2941da177e4SLinus Torvalds ldo R%tracesys_next(%r2),%r2 2951da177e4SLinus Torvalds 2961da177e4SLinus Torvaldstracesys_next: 2972798af1aSKyle McMartin /* do_syscall_trace_enter either returned the syscallno, or -1L, 2982798af1aSKyle McMartin * so we skip restoring the PT_GR20 below, since we pulled it from 2992798af1aSKyle McMartin * task->thread.regs.gr[20] above. 3002798af1aSKyle McMartin */ 3012798af1aSKyle McMartin copy %ret0,%r20 3021da177e4SLinus Torvalds ldil L%sys_call_table,%r1 3031da177e4SLinus Torvalds ldo R%sys_call_table(%r1), %r19 3041da177e4SLinus Torvalds 3051da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3061da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 3071da177e4SLinus Torvalds LDREG TASK_PT_GR26(%r1), %r26 /* Restore the users args */ 3081da177e4SLinus Torvalds LDREG TASK_PT_GR25(%r1), %r25 3091da177e4SLinus Torvalds LDREG TASK_PT_GR24(%r1), %r24 3101da177e4SLinus Torvalds LDREG TASK_PT_GR23(%r1), %r23 311413059f2SGrant Grundler#ifdef CONFIG_64BIT 3121da177e4SLinus Torvalds LDREG TASK_PT_GR22(%r1), %r22 3131da177e4SLinus Torvalds LDREG TASK_PT_GR21(%r1), %r21 3141da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3151da177e4SLinus Torvalds#endif 3161da177e4SLinus Torvalds 3171da177e4SLinus Torvalds comiclr,>>= __NR_Linux_syscalls, %r20, %r0 3181da177e4SLinus Torvalds b,n .Lsyscall_nosys 3191da177e4SLinus Torvalds 3201da177e4SLinus Torvalds LDREGX %r20(%r19), %r19 3211da177e4SLinus Torvalds 3221da177e4SLinus Torvalds /* If this is a sys_rt_sigreturn call, and the signal was received 3231da177e4SLinus Torvalds * when not in_syscall, then we want to return via syscall_exit_rfi, 3241da177e4SLinus Torvalds * not syscall_exit. Signal no. in r20, in_syscall in r25 (see 3251da177e4SLinus Torvalds * trampoline code in signal.c). 3261da177e4SLinus Torvalds */ 3271da177e4SLinus Torvalds ldi __NR_rt_sigreturn,%r2 3281da177e4SLinus Torvalds comb,= %r2,%r20,.Ltrace_rt_sigreturn 3291da177e4SLinus Torvalds.Ltrace_in_syscall: 3301da177e4SLinus Torvalds ldil L%tracesys_exit,%r2 3311da177e4SLinus Torvalds be 0(%sr7,%r19) 3321da177e4SLinus Torvalds ldo R%tracesys_exit(%r2),%r2 3331da177e4SLinus Torvalds 3341da177e4SLinus Torvalds /* Do *not* call this function on the gateway page, because it 3351da177e4SLinus Torvalds makes a direct call to syscall_trace. */ 3361da177e4SLinus Torvalds 3371da177e4SLinus Torvaldstracesys_exit: 3381da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3391da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 340413059f2SGrant Grundler#ifdef CONFIG_64BIT 3411da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3421da177e4SLinus Torvalds#endif 3432798af1aSKyle McMartin ldo TASK_REGS(%r1),%r26 3442798af1aSKyle McMartin bl do_syscall_trace_exit,%r2 3451da177e4SLinus Torvalds STREG %r28,TASK_PT_GR28(%r1) /* save return value now */ 3461da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3471da177e4SLinus Torvalds LDREG TI_TASK(%r1), %r1 3481da177e4SLinus Torvalds LDREG TASK_PT_GR28(%r1), %r28 /* Restore return val. */ 3491da177e4SLinus Torvalds 3501da177e4SLinus Torvalds ldil L%syscall_exit,%r1 3511da177e4SLinus Torvalds be,n R%syscall_exit(%sr7,%r1) 3521da177e4SLinus Torvalds 3531da177e4SLinus Torvalds.Ltrace_rt_sigreturn: 3541da177e4SLinus Torvalds comib,<> 0,%r25,.Ltrace_in_syscall 3551da177e4SLinus Torvalds ldil L%tracesys_sigexit,%r2 3561da177e4SLinus Torvalds be 0(%sr7,%r19) 3571da177e4SLinus Torvalds ldo R%tracesys_sigexit(%r2),%r2 3581da177e4SLinus Torvalds 3591da177e4SLinus Torvaldstracesys_sigexit: 3601da177e4SLinus Torvalds ldo -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1 /* get task ptr */ 3615837d42fSKyle McMartin LDREG TI_TASK(%r1), %r1 362413059f2SGrant Grundler#ifdef CONFIG_64BIT 3631da177e4SLinus Torvalds ldo -16(%r30),%r29 /* Reference param save area */ 3641da177e4SLinus Torvalds#endif 3652798af1aSKyle McMartin bl do_syscall_trace_exit,%r2 3662798af1aSKyle McMartin ldo TASK_REGS(%r1),%r26 3671da177e4SLinus Torvalds 3681da177e4SLinus Torvalds ldil L%syscall_exit_rfi,%r1 3691da177e4SLinus Torvalds be,n R%syscall_exit_rfi(%sr7,%r1) 3701da177e4SLinus Torvalds 3711da177e4SLinus Torvalds 3721da177e4SLinus Torvalds /********************************************************* 373c84c3a69SHelge Deller 32/64-bit Light-Weight-Syscall ABI 3741da177e4SLinus Torvalds 375c84c3a69SHelge Deller * - Indicates a hint for userspace inline asm 376c84c3a69SHelge Deller implementations. 3771da177e4SLinus Torvalds 378c84c3a69SHelge Deller Syscall number (caller-saves) 379c84c3a69SHelge Deller - %r20 380c84c3a69SHelge Deller * In asm clobber. 3811da177e4SLinus Torvalds 382c84c3a69SHelge Deller Argument registers (caller-saves) 383c84c3a69SHelge Deller - %r26, %r25, %r24, %r23, %r22 384c84c3a69SHelge Deller * In asm input. 385c84c3a69SHelge Deller 386c84c3a69SHelge Deller Return registers (caller-saves) 387c84c3a69SHelge Deller - %r28 (return), %r21 (errno) 388c84c3a69SHelge Deller * In asm output. 389c84c3a69SHelge Deller 390c84c3a69SHelge Deller Caller-saves registers 391c84c3a69SHelge Deller - %r1, %r27, %r29 392c84c3a69SHelge Deller - %r2 (return pointer) 393c84c3a69SHelge Deller - %r31 (ble link register) 394c84c3a69SHelge Deller * In asm clobber. 395c84c3a69SHelge Deller 396c84c3a69SHelge Deller Callee-saves registers 397c84c3a69SHelge Deller - %r3-%r18 398c84c3a69SHelge Deller - %r30 (stack pointer) 399c84c3a69SHelge Deller * Not in asm clobber. 400c84c3a69SHelge Deller 401c84c3a69SHelge Deller If userspace is 32-bit: 402c84c3a69SHelge Deller Callee-saves registers 403c84c3a69SHelge Deller - %r19 (32-bit PIC register) 404c84c3a69SHelge Deller 405c84c3a69SHelge Deller Differences from 32-bit calling convention: 406c84c3a69SHelge Deller - Syscall number in %r20 407c84c3a69SHelge Deller - Additional argument register %r22 (arg4) 408c84c3a69SHelge Deller - Callee-saves %r19. 409c84c3a69SHelge Deller 410c84c3a69SHelge Deller If userspace is 64-bit: 411c84c3a69SHelge Deller Callee-saves registers 412c84c3a69SHelge Deller - %r27 (64-bit PIC register) 413c84c3a69SHelge Deller 414c84c3a69SHelge Deller Differences from 64-bit calling convention: 415c84c3a69SHelge Deller - Syscall number in %r20 416c84c3a69SHelge Deller - Additional argument register %r22 (arg4) 417c84c3a69SHelge Deller - Callee-saves %r27. 4181da177e4SLinus Torvalds 4191da177e4SLinus Torvalds Error codes returned by entry path: 4201da177e4SLinus Torvalds 4211da177e4SLinus Torvalds ENOSYS - r20 was an invalid LWS number. 4221da177e4SLinus Torvalds 4231da177e4SLinus Torvalds *********************************************************/ 4241da177e4SLinus Torvaldslws_start: 4251da177e4SLinus Torvalds 426413059f2SGrant Grundler#ifdef CONFIG_64BIT 4271da177e4SLinus Torvalds /* FIXME: If we are a 64-bit kernel just 4281da177e4SLinus Torvalds * turn this on unconditionally. 4291da177e4SLinus Torvalds */ 4301da177e4SLinus Torvalds ssm PSW_SM_W, %r1 4311da177e4SLinus Torvalds extrd,u %r1,PSW_W_BIT,1,%r1 4321da177e4SLinus Torvalds /* sp must be aligned on 4, so deposit the W bit setting into 4331da177e4SLinus Torvalds * the bottom of sp temporarily */ 4341da177e4SLinus Torvalds or,ev %r1,%r30,%r30 4351da177e4SLinus Torvalds 4361da177e4SLinus Torvalds /* Clip LWS number to a 32-bit value always */ 4371da177e4SLinus Torvalds depdi 0, 31, 32, %r20 4381da177e4SLinus Torvalds#endif 4391da177e4SLinus Torvalds 4401da177e4SLinus Torvalds /* Is the lws entry number valid? */ 441f4c0346cSJohn David Anglin comiclr,>> __NR_lws_entries, %r20, %r0 4421da177e4SLinus Torvalds b,n lws_exit_nosys 4431da177e4SLinus Torvalds 4441da177e4SLinus Torvalds /* WARNING: Trashing sr2 and sr3 */ 4451da177e4SLinus Torvalds mfsp %sr7,%r1 /* get userspace into sr3 */ 4461da177e4SLinus Torvalds mtsp %r1,%sr3 4471da177e4SLinus Torvalds mtsp %r0,%sr2 /* get kernel space into sr2 */ 4481da177e4SLinus Torvalds 4491da177e4SLinus Torvalds /* Load table start */ 4501da177e4SLinus Torvalds ldil L%lws_table, %r1 4511da177e4SLinus Torvalds ldo R%lws_table(%r1), %r28 /* Scratch use of r28 */ 4521da177e4SLinus Torvalds LDREGX %r20(%sr2,r28), %r21 /* Scratch use of r21 */ 4531da177e4SLinus Torvalds 4541da177e4SLinus Torvalds /* Jump to lws, lws table pointers already relocated */ 4551da177e4SLinus Torvalds be,n 0(%sr2,%r21) 4561da177e4SLinus Torvalds 4571da177e4SLinus Torvaldslws_exit_nosys: 4581da177e4SLinus Torvalds ldo -ENOSYS(%r0),%r21 /* set errno */ 4591da177e4SLinus Torvalds /* Fall through: Return to userspace */ 4601da177e4SLinus Torvalds 4611da177e4SLinus Torvaldslws_exit: 462413059f2SGrant Grundler#ifdef CONFIG_64BIT 4631da177e4SLinus Torvalds /* decide whether to reset the wide mode bit 4641da177e4SLinus Torvalds * 4651da177e4SLinus Torvalds * For a syscall, the W bit is stored in the lowest bit 4661da177e4SLinus Torvalds * of sp. Extract it and reset W if it is zero */ 4671da177e4SLinus Torvalds extrd,u,*<> %r30,63,1,%r1 4681da177e4SLinus Torvalds rsm PSW_SM_W, %r0 4691da177e4SLinus Torvalds /* now reset the lowest bit of sp if it was set */ 4701da177e4SLinus Torvalds xor %r30,%r1,%r30 4711da177e4SLinus Torvalds#endif 472f4c0346cSJohn David Anglin be,n 0(%sr7, %r31) 4731da177e4SLinus Torvalds 4741da177e4SLinus Torvalds 4751da177e4SLinus Torvalds 4761da177e4SLinus Torvalds /*************************************************** 4771da177e4SLinus Torvalds Implementing CAS as an atomic operation: 4781da177e4SLinus Torvalds 4791da177e4SLinus Torvalds %r26 - Address to examine 4801da177e4SLinus Torvalds %r25 - Old value to check (old) 4811da177e4SLinus Torvalds %r24 - New value to set (new) 4821da177e4SLinus Torvalds %r28 - Return prev through this register. 4831da177e4SLinus Torvalds %r21 - Kernel error code 4841da177e4SLinus Torvalds 4851da177e4SLinus Torvalds If debugging is DISabled: 4861da177e4SLinus Torvalds 4871da177e4SLinus Torvalds %r21 has the following meanings: 4881da177e4SLinus Torvalds 4891da177e4SLinus Torvalds EAGAIN - CAS is busy, ldcw failed, try again. 4901da177e4SLinus Torvalds EFAULT - Read or write failed. 4911da177e4SLinus Torvalds 4921da177e4SLinus Torvalds If debugging is enabled: 4931da177e4SLinus Torvalds 4941da177e4SLinus Torvalds EDEADLOCK - CAS called recursively. 4951da177e4SLinus Torvalds EAGAIN && r28 == 1 - CAS is busy. Lock contended. 4961da177e4SLinus Torvalds EAGAIN && r28 == 2 - CAS is busy. ldcw failed. 4971da177e4SLinus Torvalds EFAULT - Read or write failed. 4981da177e4SLinus Torvalds 4991da177e4SLinus Torvalds Scratch: r20, r28, r1 5001da177e4SLinus Torvalds 5011da177e4SLinus Torvalds ****************************************************/ 5021da177e4SLinus Torvalds 5031da177e4SLinus Torvalds /* Do not enable LWS debugging */ 5041da177e4SLinus Torvalds#define ENABLE_LWS_DEBUG 0 5051da177e4SLinus Torvalds 5061da177e4SLinus Torvalds /* ELF64 Process entry path */ 5071da177e4SLinus Torvaldslws_compare_and_swap64: 508413059f2SGrant Grundler#ifdef CONFIG_64BIT 5091da177e4SLinus Torvalds b,n lws_compare_and_swap 5101da177e4SLinus Torvalds#else 5111da177e4SLinus Torvalds /* If we are not a 64-bit kernel, then we don't 512c84c3a69SHelge Deller * have 64-bit input registers, and calling 513c84c3a69SHelge Deller * the 64-bit LWS CAS returns ENOSYS. 5141da177e4SLinus Torvalds */ 5151da177e4SLinus Torvalds b,n lws_exit_nosys 5161da177e4SLinus Torvalds#endif 5171da177e4SLinus Torvalds 5181da177e4SLinus Torvalds /* ELF32 Process entry path */ 5191da177e4SLinus Torvaldslws_compare_and_swap32: 520413059f2SGrant Grundler#ifdef CONFIG_64BIT 5211da177e4SLinus Torvalds /* Clip all the input registers */ 5221da177e4SLinus Torvalds depdi 0, 31, 32, %r26 5231da177e4SLinus Torvalds depdi 0, 31, 32, %r25 5241da177e4SLinus Torvalds depdi 0, 31, 32, %r24 5251da177e4SLinus Torvalds#endif 5261da177e4SLinus Torvalds 5271da177e4SLinus Torvaldslws_compare_and_swap: 5281da177e4SLinus Torvalds /* Load start of lock table */ 5291da177e4SLinus Torvalds ldil L%lws_lock_start, %r20 5301da177e4SLinus Torvalds ldo R%lws_lock_start(%r20), %r28 5311da177e4SLinus Torvalds 5321da177e4SLinus Torvalds /* Extract four bits from r26 and hash lock (Bits 4-7) */ 5331da177e4SLinus Torvalds extru %r26, 27, 4, %r20 5341da177e4SLinus Torvalds 5351da177e4SLinus Torvalds /* Find lock to use, the hash is either one of 0 to 5361da177e4SLinus Torvalds 15, multiplied by 16 (keep it 16-byte aligned) 5371da177e4SLinus Torvalds and add to the lock table offset. */ 5381da177e4SLinus Torvalds shlw %r20, 4, %r20 5391da177e4SLinus Torvalds add %r20, %r28, %r20 5401da177e4SLinus Torvalds 541b5e8b733SAurelien Jarno# if ENABLE_LWS_DEBUG 5421da177e4SLinus Torvalds /* 5431da177e4SLinus Torvalds DEBUG, check for deadlock! 5441da177e4SLinus Torvalds If the thread register values are the same 5451da177e4SLinus Torvalds then we were the one that locked it last and 5461da177e4SLinus Torvalds this is a recurisve call that will deadlock. 5471da177e4SLinus Torvalds We *must* giveup this call and fail. 5481da177e4SLinus Torvalds */ 5491da177e4SLinus Torvalds ldw 4(%sr2,%r20), %r28 /* Load thread register */ 550aa0eecb0SCarlos O'Donell /* WARNING: If cr27 cycles to the same value we have problems */ 5511da177e4SLinus Torvalds mfctl %cr27, %r21 /* Get current thread register */ 5521da177e4SLinus Torvalds cmpb,<>,n %r21, %r28, cas_lock /* Called recursive? */ 5531da177e4SLinus Torvalds b lws_exit /* Return error! */ 5541da177e4SLinus Torvalds ldo -EDEADLOCK(%r0), %r21 5551da177e4SLinus Torvaldscas_lock: 5561da177e4SLinus Torvalds cmpb,=,n %r0, %r28, cas_nocontend /* Is nobody using it? */ 5571da177e4SLinus Torvalds ldo 1(%r0), %r28 /* 1st case */ 5581da177e4SLinus Torvalds b lws_exit /* Contended... */ 5591da177e4SLinus Torvalds ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 5601da177e4SLinus Torvaldscas_nocontend: 5611da177e4SLinus Torvalds# endif 5621da177e4SLinus Torvalds/* ENABLE_LWS_DEBUG */ 5631da177e4SLinus Torvalds 56464f49532SKyle McMartin LDCW 0(%sr2,%r20), %r28 /* Try to acquire the lock */ 5651da177e4SLinus Torvalds cmpb,<>,n %r0, %r28, cas_action /* Did we get it? */ 5661da177e4SLinus Torvaldscas_wouldblock: 5671da177e4SLinus Torvalds ldo 2(%r0), %r28 /* 2nd case */ 5681da177e4SLinus Torvalds b lws_exit /* Contended... */ 5691da177e4SLinus Torvalds ldo -EAGAIN(%r0), %r21 /* Spin in userspace */ 5701da177e4SLinus Torvalds 5711da177e4SLinus Torvalds /* 5721da177e4SLinus Torvalds prev = *addr; 5731da177e4SLinus Torvalds if ( prev == old ) 5741da177e4SLinus Torvalds *addr = new; 5751da177e4SLinus Torvalds return prev; 5761da177e4SLinus Torvalds */ 5771da177e4SLinus Torvalds 5781da177e4SLinus Torvalds /* NOTES: 5791da177e4SLinus Torvalds This all works becuse intr_do_signal 5801da177e4SLinus Torvalds and schedule both check the return iasq 5811da177e4SLinus Torvalds and see that we are on the kernel page 5821da177e4SLinus Torvalds so this process is never scheduled off 5831da177e4SLinus Torvalds or is ever sent any signal of any sort, 5841da177e4SLinus Torvalds thus it is wholly atomic from usrspaces 5851da177e4SLinus Torvalds perspective 5861da177e4SLinus Torvalds */ 5871da177e4SLinus Torvaldscas_action: 588b5e8b733SAurelien Jarno#if defined CONFIG_SMP && ENABLE_LWS_DEBUG 5891da177e4SLinus Torvalds /* DEBUG */ 5901da177e4SLinus Torvalds mfctl %cr27, %r1 5911da177e4SLinus Torvalds stw %r1, 4(%sr2,%r20) 5921da177e4SLinus Torvalds#endif 5931da177e4SLinus Torvalds /* The load and store could fail */ 5941da177e4SLinus Torvalds1: ldw 0(%sr3,%r26), %r28 5951da177e4SLinus Torvalds sub,<> %r28, %r25, %r0 5961da177e4SLinus Torvalds2: stw %r24, 0(%sr3,%r26) 5971da177e4SLinus Torvalds /* Free lock */ 5981da177e4SLinus Torvalds stw %r20, 0(%sr2,%r20) 599b5e8b733SAurelien Jarno#if ENABLE_LWS_DEBUG 6001da177e4SLinus Torvalds /* Clear thread register indicator */ 6011da177e4SLinus Torvalds stw %r0, 4(%sr2,%r20) 6021da177e4SLinus Torvalds#endif 6031da177e4SLinus Torvalds /* Return to userspace, set no error */ 6041da177e4SLinus Torvalds b lws_exit 6051da177e4SLinus Torvalds copy %r0, %r21 6061da177e4SLinus Torvalds 6071da177e4SLinus Torvalds3: 60825985edcSLucas De Marchi /* Error occurred on load or store */ 6091da177e4SLinus Torvalds /* Free lock */ 6101da177e4SLinus Torvalds stw %r20, 0(%sr2,%r20) 611b5e8b733SAurelien Jarno#if ENABLE_LWS_DEBUG 6121da177e4SLinus Torvalds stw %r0, 4(%sr2,%r20) 6131da177e4SLinus Torvalds#endif 6141da177e4SLinus Torvalds b lws_exit 6151da177e4SLinus Torvalds ldo -EFAULT(%r0),%r21 /* set errno */ 6161da177e4SLinus Torvalds nop 6171da177e4SLinus Torvalds nop 6181da177e4SLinus Torvalds nop 6191da177e4SLinus Torvalds nop 6201da177e4SLinus Torvalds 6211da177e4SLinus Torvalds /* Two exception table entries, one for the load, 6221da177e4SLinus Torvalds the other for the store. Either return -EFAULT. 6231da177e4SLinus Torvalds Each of the entries must be relocated. */ 6241da177e4SLinus Torvalds .section __ex_table,"aw" 6250b3d643fSHelge Deller ASM_ULONG_INSN (1b - linux_gateway_page), (3b - linux_gateway_page) 6260b3d643fSHelge Deller ASM_ULONG_INSN (2b - linux_gateway_page), (3b - linux_gateway_page) 6271da177e4SLinus Torvalds .previous 6281da177e4SLinus Torvalds 6291da177e4SLinus Torvalds 6301da177e4SLinus Torvalds /* Make sure nothing else is placed on this page */ 6311c593571SSam Ravnborg .align PAGE_SIZE 6328e9e9844SHelge DellerEND(linux_gateway_page) 6338e9e9844SHelge DellerENTRY(end_linux_gateway_page) 6341da177e4SLinus Torvalds 6351da177e4SLinus Torvalds /* Relocate symbols assuming linux_gateway_page is mapped 6361da177e4SLinus Torvalds to virtual address 0x0 */ 6378e9e9844SHelge Deller 6380b3d643fSHelge Deller#define LWS_ENTRY(_name_) ASM_ULONG_INSN (lws_##_name_ - linux_gateway_page) 6391da177e4SLinus Torvalds 6401bcdd854SHelge Deller .section .rodata,"a" 6411bcdd854SHelge Deller 6421c593571SSam Ravnborg .align PAGE_SIZE 6431da177e4SLinus Torvalds /* Light-weight-syscall table */ 6441da177e4SLinus Torvalds /* Start of lws table. */ 6458e9e9844SHelge DellerENTRY(lws_table) 6461da177e4SLinus Torvalds LWS_ENTRY(compare_and_swap32) /* 0 - ELF32 Atomic compare and swap */ 6471da177e4SLinus Torvalds LWS_ENTRY(compare_and_swap64) /* 1 - ELF64 Atomic compare and swap */ 6488e9e9844SHelge DellerEND(lws_table) 6491da177e4SLinus Torvalds /* End of lws table */ 6501da177e4SLinus Torvalds 6511c593571SSam Ravnborg .align PAGE_SIZE 6528e9e9844SHelge DellerENTRY(sys_call_table) 6531da177e4SLinus Torvalds#include "syscall_table.S" 6548e9e9844SHelge DellerEND(sys_call_table) 6551da177e4SLinus Torvalds 656413059f2SGrant Grundler#ifdef CONFIG_64BIT 6571c593571SSam Ravnborg .align PAGE_SIZE 6588e9e9844SHelge DellerENTRY(sys_call_table64) 6591da177e4SLinus Torvalds#define SYSCALL_TABLE_64BIT 6601da177e4SLinus Torvalds#include "syscall_table.S" 6618e9e9844SHelge DellerEND(sys_call_table64) 6621da177e4SLinus Torvalds#endif 6631da177e4SLinus Torvalds 6641da177e4SLinus Torvalds /* 6651da177e4SLinus Torvalds All light-weight-syscall atomic operations 6661da177e4SLinus Torvalds will use this set of locks 667c84c3a69SHelge Deller 668c84c3a69SHelge Deller NOTE: The lws_lock_start symbol must be 669c84c3a69SHelge Deller at least 16-byte aligned for safe use 670c84c3a69SHelge Deller with ldcw. 6711da177e4SLinus Torvalds */ 672dfcf753bSKyle McMartin .section .data 673873d50e2SKyle McMartin .align PAGE_SIZE 6748e9e9844SHelge DellerENTRY(lws_lock_start) 6751da177e4SLinus Torvalds /* lws locks */ 6761da177e4SLinus Torvalds .rept 16 6771da177e4SLinus Torvalds /* Keep locks aligned at 16-bytes */ 6781da177e4SLinus Torvalds .word 1 6791da177e4SLinus Torvalds .word 0 6801da177e4SLinus Torvalds .word 0 6811da177e4SLinus Torvalds .word 0 6821da177e4SLinus Torvalds .endr 6838e9e9844SHelge DellerEND(lws_lock_start) 6841da177e4SLinus Torvalds .previous 6851da177e4SLinus Torvalds 6861da177e4SLinus Torvalds.end 6871da177e4SLinus Torvalds 6881da177e4SLinus Torvalds 689