diff options
| author |   Andy Lutomirski <luto@kernel.org> | 2015-10-05 17:48:05 -0700 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2015-10-09 09:41:07 +0200 |
| commit | 8169aff611956ed360e3313e8c718f530f58f6cb (patch) | |
| tree | afd865482d5cf9ec39800fb06d87f35ef7dfb4c5 /arch/x86/entry/entry_64_compat.S | |
| parent | x86/entry/64/compat: Remove most of the fast system call machinery (diff) | |
| download | linux-dev-8169aff611956ed360e3313e8c718f530f58f6cb.tar.xz linux-dev-8169aff611956ed360e3313e8c718f530f58f6cb.zip | |
x86/entry/64/compat: Set up full pt_regs for all compat syscalls
This is conceptually simpler. More importantly, it eliminates
the PTREGSCALL and execve stubs, which were not compatible with
the C ABI. This means that C code can call through the compat
syscall table.
The execve stubs are a bit subtle. They did two things: they
cleared some registers and they forced slow-path return.
Neither is necessary any more: elf_common_init clears the extra
registers and start_thread calls force_iret().
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/f95b7f7dfaacf88a8cae85bb06226cae53769287.1444091584.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 | 42 |
1 files changed, 13 insertions, 29 deletions
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 3216e6072312..2c2aac577b3c 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -219,12 +219,18 @@ ENTRY(entry_INT80_compat) pushq %rdx /* pt_regs->dx */ pushq %rcx /* pt_regs->cx */ pushq $-ENOSYS /* pt_regs->ax */ - pushq $0 /* pt_regs->r8 */ - pushq $0 /* pt_regs->r9 */ - pushq $0 /* pt_regs->r10 */ - pushq $0 /* pt_regs->r11 */ + xorq %r8,%r8 + pushq %r8 /* pt_regs->r8 = 0 */ + pushq %r8 /* pt_regs->r9 = 0 */ + pushq %r8 /* pt_regs->r10 = 0 */ + pushq %r8 /* pt_regs->r11 = 0 */ + pushq %rbx /* pt_regs->rbx */ + pushq %rbp /* pt_regs->rbp */ + pushq %r12 /* pt_regs->r12 */ + pushq %r13 /* pt_regs->r13 */ + pushq %r14 /* pt_regs->r14 */ + pushq %r15 /* pt_regs->r15 */ cld - sub $(6*8), %rsp /* pt_regs->bp, bx, r12-15 not saved */ orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS) testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) @@ -243,10 +249,10 @@ ia32_do_call: call *ia32_sys_call_table(, %rax, 8) movq %rax, RAX(%rsp) 1: + RESTORE_EXTRA_REGS jmp int_ret_from_sys_call ia32_tracesys: - SAVE_EXTRA_REGS movq %rsp, %rdi /* &pt_regs -> arg1 */ call syscall_trace_enter /* @@ -261,25 +267,11 @@ ia32_tracesys: movl RSI(%rsp), %esi movl RDI(%rsp), %edi movl %eax, %eax /* zero extension */ - RESTORE_EXTRA_REGS jmp ia32_do_call END(entry_INT80_compat) - .macro PTREGSCALL label, func - ALIGN -GLOBAL(\label) - leaq \func(%rip), %rax - jmp ia32_ptregs_common - .endm - - PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn - PTREGSCALL stub32_sigreturn, sys32_sigreturn - PTREGSCALL stub32_fork, sys_fork - PTREGSCALL stub32_vfork, sys_vfork - ALIGN GLOBAL(stub32_clone) - leaq sys_clone(%rip), %rax /* * The 32-bit clone ABI is: clone(..., int tls_val, int *child_tidptr). * The 64-bit clone ABI is: clone(..., int *child_tidptr, int tls_val). @@ -288,12 +280,4 @@ GLOBAL(stub32_clone) * so we need to swap arguments here before calling it: */ xchg %r8, %rcx - jmp ia32_ptregs_common - - ALIGN -ia32_ptregs_common: - SAVE_EXTRA_REGS 8 - call *%rax - RESTORE_EXTRA_REGS 8 - ret -END(ia32_ptregs_common) + jmp sys_clone |