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| author |   Andy Lutomirski <luto@kernel.org> | 2015-10-05 17:48:09 -0700 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2015-10-09 09:41:09 +0200 |
| commit | ee08c6bd315e70756ad2c47ee6ea708a4a882b55 (patch) | |
| tree | de6af827765c53c23d15b7b15fa619b1d898f19d /arch/x86/entry/entry_64_compat.S | |
| parent | x86/entry: Add do_syscall_32(), a C function to do 32-bit syscalls (diff) | |
| download | linux-dev-ee08c6bd315e70756ad2c47ee6ea708a4a882b55.tar.xz linux-dev-ee08c6bd315e70756ad2c47ee6ea708a4a882b55.zip | |
x86/entry/64/compat: Migrate the body of the syscall entry to C
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/a2f0fce68feeba798a24339b5a7ec1ec2dd9eaf7.1444091585.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/entry/entry_64_compat.S')
| -rw-r--r-- | arch/x86/entry/entry_64_compat.S | 56 |
1 files changed, 18 insertions, 38 deletions
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 2c2aac577b3c..63ef9fa29002 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -202,14 +202,17 @@ END(entry_SYSCALL_compat) ENTRY(entry_INT80_compat) /* * Interrupts are off on entry. - * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON, - * it is too small to ever cause noticeable irq latency. */ PARAVIRT_ADJUST_EXCEPTION_FRAME SWAPGS - ENABLE_INTERRUPTS(CLBR_NONE) - /* Zero-extending 32-bit regs, do not remove */ + /* + * User tracing code (ptrace or signal handlers) might assume that + * the saved RAX contains a 32-bit number when we're invoking a 32-bit + * syscall. Just in case the high bits are nonzero, zero-extend + * the syscall number. (This could almost certainly be deleted + * with no ill effects.) + */ movl %eax, %eax /* Construct struct pt_regs on stack (iret frame is already on stack) */ @@ -232,42 +235,19 @@ ENTRY(entry_INT80_compat) pushq %r15 /* pt_regs->r15 */ cld - orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS) - testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) - jnz ia32_tracesys - -ia32_do_call: - /* 32-bit syscall -> 64-bit C ABI argument conversion */ - movl %edi, %r8d /* arg5 */ - movl %ebp, %r9d /* arg6 */ - xchg %ecx, %esi /* rsi:arg2, rcx:arg4 */ - movl %ebx, %edi /* arg1 */ - movl %edx, %edx /* arg3 (zero extension) */ - cmpq $(IA32_NR_syscalls-1), %rax - ja 1f - - call *ia32_sys_call_table(, %rax, 8) - movq %rax, RAX(%rsp) -1: - RESTORE_EXTRA_REGS - jmp int_ret_from_sys_call - -ia32_tracesys: - movq %rsp, %rdi /* &pt_regs -> arg1 */ - call syscall_trace_enter /* - * Reload arg registers from stack in case ptrace changed them. - * Don't reload %eax because syscall_trace_enter() returned - * the %rax value we should see. But do truncate it to 32 bits. - * If it's -1 to make us punt the syscall, then (u32)-1 is still - * an appropriately invalid value. + * User mode is traced as though IRQs are on, and the interrupt + * gate turned them off. */ - movl RCX(%rsp), %ecx - movl RDX(%rsp), %edx - movl RSI(%rsp), %esi - movl RDI(%rsp), %edi - movl %eax, %eax /* zero extension */ - jmp ia32_do_call + TRACE_IRQS_OFF + + movq %rsp, %rdi + call do_int80_syscall_32 + + /* Go back to user mode. */ + TRACE_IRQS_ON + SWAPGS + jmp restore_regs_and_iret END(entry_INT80_compat) ALIGN |