This macro is small, has only three callsites, and one of them is slightly different using a conditional parameter.
A few saved lines aren't worth the resulting obfuscation. Generated machine code is identical. Signed-off-by: Denys Vlasenko <[email protected]> CC: Linus Torvalds <[email protected]> CC: Steven Rostedt <[email protected]> CC: Ingo Molnar <[email protected]> CC: Borislav Petkov <[email protected]> CC: "H. Peter Anvin" <[email protected]> CC: Andy Lutomirski <[email protected]> CC: Oleg Nesterov <[email protected]> CC: Frederic Weisbecker <[email protected]> CC: Alexei Starovoitov <[email protected]> CC: Will Drewry <[email protected]> CC: Kees Cook <[email protected]> CC: [email protected] CC: [email protected] --- arch/x86/ia32/ia32entry.S | 62 ++++++++++++++++++++++++++++------------------- 1 file changed, 37 insertions(+), 25 deletions(-) diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index 86cbfe6..0ff676a 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -29,28 +29,6 @@ .section .entry.text, "ax" - /* - * Reload arg registers from stack in case ptrace changed them. - * We don't reload %eax because syscall_trace_enter() returned - * the %rax value we should see. Instead, we just truncate that - * value to 32 bits again as we did on entry from user mode. - * If it's a new value set by user_regset during entry tracing, - * this matches the normal truncation of the user-mode value. - * If it's -1 to make us punt the syscall, then (u32)-1 is still - * an appropriately invalid value. - */ - .macro LOAD_ARGS32 _r9=0 - .if \_r9 - movl R9(%rsp),%r9d - .endif - movl RCX(%rsp),%ecx - movl RDX(%rsp),%edx - movl RSI(%rsp),%esi - movl RDI(%rsp),%edi - movl %eax,%eax /* zero extension */ - .endm - - #ifdef CONFIG_PARAVIRT ENTRY(native_usergs_sysret32) swapgs @@ -269,7 +247,18 @@ sysenter_tracesys: movq %rax, R8(%rsp) movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter - LOAD_ARGS32 /* reload args from stack in case ptrace changed it */ + /* + * 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. + */ + movl RCX(%rsp), %ecx + movl RDX(%rsp), %edx + movl RSI(%rsp), %esi + movl RDI(%rsp), %edi + movl %eax, %eax /* zero extension */ RESTORE_EXTRA_REGS jmp sysenter_do_call ENDPROC(ia32_sysenter_target) @@ -413,7 +402,19 @@ cstar_tracesys: movq %rax, R8(%rsp) movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter - LOAD_ARGS32 1 /* reload args from stack in case ptrace changed it */ + movl R9(%rsp),%r9d + /* + * 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. + */ + movl RCX(%rsp), %ecx + movl RDX(%rsp), %edx + movl RSI(%rsp), %esi + movl RDI(%rsp), %edi + movl %eax, %eax /* zero extension */ RESTORE_EXTRA_REGS xchgl %ebp,%r9d jmp cstar_do_call @@ -502,7 +503,18 @@ ia32_tracesys: SAVE_EXTRA_REGS movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter - LOAD_ARGS32 /* reload args from stack in case ptrace changed it */ + /* + * 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. + */ + movl RCX(%rsp), %ecx + movl RDX(%rsp), %edx + movl RSI(%rsp), %esi + movl RDI(%rsp), %edi + movl %eax, %eax /* zero extension */ RESTORE_EXTRA_REGS jmp ia32_do_call END(ia32_syscall) -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
