From: Denys Vlasenko Date: Sun, 7 Jun 2015 18:24:30 +0000 (+0200) Subject: x86/asm/entry/32: Reinstate clearing of pt_regs->r8..r11 on EFAULT path X-Git-Url: http://git.efficios.com/?a=commitdiff_plain;h=eb47854415825a69b1c578e7487da571227ba25a;p=deliverable%2Flinux.git x86/asm/entry/32: Reinstate clearing of pt_regs->r8..r11 on EFAULT path I broke this recently when I changed pt_regs->r8..r11 clearing logic in INT 80 code path. There is a branch from SYSENTER/SYSCALL code to INT 80 code: if we fail to retrieve arg6, we return EFAULT. Before this patch, in this case we don't clear pt_regs->r8..r11. This patch fixes this. The resulting code is smaller and simpler. While at it, remove incorrect comment about syscall dispatching CALL insn: it does not use RIP-relative addressing form (the comment was meant to be "TODO: make this rip-relative", and morphed since then, dropping "TODO"). Signed-off-by: Denys Vlasenko Cc: Alexei Starovoitov Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Will Drewry Link: http://lkml.kernel.org/r/1433701470-28800-1-git-send-email-dvlasenk@redhat.com Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 59840e33d203..5757ddec35d6 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -413,9 +413,7 @@ END(entry_SYSCALL_compat) ia32_badarg: ASM_CLAC - movq $-EFAULT, %rax - jmp ia32_sysret - + movq $-EFAULT, RAX(%rsp) ia32_ret_from_sys_call: xorl %eax, %eax /* Do not leak kernel information */ movq %rax, R11(%rsp) @@ -486,9 +484,7 @@ ia32_do_call: cmpq $(IA32_NR_syscalls-1), %rax ja 1f - call *ia32_sys_call_table(, %rax, 8) /* RIP relative */ - -ia32_sysret: + call *ia32_sys_call_table(, %rax, 8) movq %rax, RAX(%rsp) 1: jmp int_ret_from_sys_call