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linux/arch/powerpc/kernel/systbl.S

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* This file contains the table of syscall-handling functions.
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
* and Paul Mackerras.
*
* Adapted for iSeries by Mike Corrigan (mikejc@us.ibm.com)
* PPC64 updates by Dave Engebretsen (engebret@us.ibm.com)
*/
#include <asm/ppc_asm.h>
.section .rodata,"a"
#ifdef CONFIG_PPC64
.p2align 3
powerpc/64/sycall: Implement syscall entry/exit logic in C System call entry and particularly exit code is beyond the limit of what is reasonable to implement in asm. This conversion moves all conditional branches out of the asm code, except for the case that all GPRs should be restored at exit. Null syscall test is about 5% faster after this patch, because the exit work is handled under local_irq_disable, and the hard mask and pending interrupt replay is handled after that, which avoids games with MSR. mpe: Includes subsequent fixes from Nick: This fixes 4 issues caught by TM selftests. First was a tm-syscall bug that hit due to tabort_syscall being called after interrupts were reconciled (in a subsequent patch), which led to interrupts being enabled before tabort_syscall was called. Rather than going through an un-reconciling interrupts for the return, I just go back to putting the test early in asm, the C-ification of that wasn't a big win anyway. Second is the syscall return _TIF_USER_WORK_MASK check would go into an infinite loop if _TIF_RESTORE_TM became set. The asm code uses _TIF_USER_WORK_MASK to brach to slowpath which includes restore_tm_state. Third is system call return was not calling restore_tm_state, I missed this completely (alhtough it's in the return from interrupt C conversion because when the asm syscall code encountered problems it would branch to the interrupt return code. Fourth is MSR_VEC missing from restore_math, which was caught by tm-unavailable selftest taking an unexpected facility unavailable interrupt when testing VSX unavailble exception with MSR.FP=1 MSR.VEC=1. Fourth case also has a fixup in a subsequent patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200225173541.1549955-26-npiggin@gmail.com
2020-02-26 03:35:34 +10:00
#define __SYSCALL(nr, entry) .8byte entry
#else
powerpc: align syscall table for ppc32 Christophe Leroy reported that commit 7b4537199a4a ("kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS") broke mpc85xx_defconfig + CONFIG_RELOCATABLE=y. LD vmlinux SYSMAP System.map SORTTAB vmlinux CHKREL vmlinux WARNING: 451 bad relocations c0b312a9 R_PPC_UADDR32 .head.text-0x3ff9ed54 c0b312ad R_PPC_UADDR32 .head.text-0x3ffac224 c0b312b1 R_PPC_UADDR32 .head.text-0x3ffb09f4 c0b312b5 R_PPC_UADDR32 .head.text-0x3fe184dc c0b312b9 R_PPC_UADDR32 .head.text-0x3fe183a8 ... The compiler emits a bunch of R_PPC_UADDR32, which is not supported by arch/powerpc/kernel/reloc_32.S. The reason is there exists an unaligned symbol. $ powerpc-linux-gnu-nm -n vmlinux ... c0b31258 d spe_aligninfo c0b31298 d __func__.0 c0b312a9 D sys_call_table c0b319b8 d __func__.0 Commit 7b4537199a4a is not the root cause. Even before that, I can reproduce the same issue for mpc85xx_defconfig + CONFIG_RELOCATABLE=y + CONFIG_MODVERSIONS=n. It is just that nobody noticed because when CONFIG_MODVERSIONS is enabled, a __crc_* symbol inserted before sys_call_table was hiding the unalignment issue. Adding alignment to the syscall table for ppc32 fixes the issue. Cc: stable@vger.kernel.org Reported-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu> [mpe: Trim change log discussion, add Cc stable] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/lkml/38605f6a-a568-f884-f06f-ea4da5b214f0@csgroup.eu/ Link: https://lore.kernel.org/r/20220820165129.1147589-1-masahiroy@kernel.org
2022-08-21 01:51:29 +09:00
.p2align 2
powerpc/64/sycall: Implement syscall entry/exit logic in C System call entry and particularly exit code is beyond the limit of what is reasonable to implement in asm. This conversion moves all conditional branches out of the asm code, except for the case that all GPRs should be restored at exit. Null syscall test is about 5% faster after this patch, because the exit work is handled under local_irq_disable, and the hard mask and pending interrupt replay is handled after that, which avoids games with MSR. mpe: Includes subsequent fixes from Nick: This fixes 4 issues caught by TM selftests. First was a tm-syscall bug that hit due to tabort_syscall being called after interrupts were reconciled (in a subsequent patch), which led to interrupts being enabled before tabort_syscall was called. Rather than going through an un-reconciling interrupts for the return, I just go back to putting the test early in asm, the C-ification of that wasn't a big win anyway. Second is the syscall return _TIF_USER_WORK_MASK check would go into an infinite loop if _TIF_RESTORE_TM became set. The asm code uses _TIF_USER_WORK_MASK to brach to slowpath which includes restore_tm_state. Third is system call return was not calling restore_tm_state, I missed this completely (alhtough it's in the return from interrupt C conversion because when the asm syscall code encountered problems it would branch to the interrupt return code. Fourth is MSR_VEC missing from restore_math, which was caught by tm-unavailable selftest taking an unexpected facility unavailable interrupt when testing VSX unavailble exception with MSR.FP=1 MSR.VEC=1. Fourth case also has a fixup in a subsequent patch. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200225173541.1549955-26-npiggin@gmail.com
2020-02-26 03:35:34 +10:00
#define __SYSCALL(nr, entry) .long entry
#endif
#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native)
.globl sys_call_table
sys_call_table:
#ifdef CONFIG_PPC64
#include <asm/syscall_table_64.h>
#else
#include <asm/syscall_table_32.h>
#endif
#ifdef CONFIG_COMPAT
#undef __SYSCALL_WITH_COMPAT
#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, compat)
.globl compat_sys_call_table
compat_sys_call_table:
#define compat_sys_sigsuspend sys_sigsuspend
#include <asm/syscall_table_32.h>
#endif