From 36197c92a20c142fc2a068e0366053d770fa0096 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Wed, 30 Jan 2008 13:30:43 +0100 Subject: [PATCH] x86 vDSO: ia32 sysenter_return This changes the 64-bit kernel's support for the 32-bit sysenter instruction to use stored fields rather than constants for the user-mode return address, as the 32-bit kernel does. This adds a sysenter_return field to struct thread_info, as 32-bit has. There is no observable effect from this yet. It makes the assembly code independent of the 32-bit vDSO mapping address, paving the way for making the vDSO address vary as it does on the 32-bit kernel. [ akpm@linux-foundation.org: build fix on !CONFIG_IA32_EMULATION ] Signed-off-by: Roland McGrath Cc: Andrew Morton Cc: Linus Torvalds Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/ia32/ia32entry.S | 7 +++---- arch/x86/ia32/syscall32.c | 4 ++++ arch/x86/kernel/asm-offsets_64.c | 3 +++ include/asm-x86/thread_info_64.h | 3 +++ 4 files changed, 13 insertions(+), 4 deletions(-) diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index df588f0f76..2499a324fe 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -12,7 +12,6 @@ #include #include #include -#include #include #include @@ -104,7 +103,7 @@ ENTRY(ia32_sysenter_target) pushfq CFI_ADJUST_CFA_OFFSET 8 /*CFI_REL_OFFSET rflags,0*/ - movl $VSYSCALL32_SYSEXIT, %r10d + movl 8*3-THREAD_SIZE+threadinfo_sysenter_return(%rsp), %r10d CFI_REGISTER rip,r10 pushq $__USER32_CS CFI_ADJUST_CFA_OFFSET 8 @@ -142,6 +141,8 @@ sysenter_do_call: andl $~TS_COMPAT,threadinfo_status(%r10) /* clear IF, that popfq doesn't enable interrupts early */ andl $~0x200,EFLAGS-R11(%rsp) + movl RIP-R11(%rsp),%edx /* User %eip */ + CFI_REGISTER rip,rdx RESTORE_ARGS 1,24,1,1,1,1 popfq CFI_ADJUST_CFA_OFFSET -8 @@ -149,8 +150,6 @@ sysenter_do_call: popq %rcx /* User %esp */ CFI_ADJUST_CFA_OFFSET -8 CFI_REGISTER rsp,rcx - movl $VSYSCALL32_SYSEXIT,%edx /* User %eip */ - CFI_REGISTER rip,rdx TRACE_IRQS_ON swapgs sti /* sti only takes effect after the next instruction */ diff --git a/arch/x86/ia32/syscall32.c b/arch/x86/ia32/syscall32.c index d751d96c2e..98ff99f5b5 100644 --- a/arch/x86/ia32/syscall32.c +++ b/arch/x86/ia32/syscall32.c @@ -46,6 +46,10 @@ int syscall32_setup_pages(struct linux_binprm *bprm, int exstack) VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC| VM_ALWAYSDUMP, syscall32_pages); + if (ret == 0) { + current->mm->context.vdso = (void __user *)VSYSCALL32_BASE; + current_thread_info()->sysenter_return = VSYSCALL32_SYSEXIT; + } up_write(&mm->mmap_sem); return ret; } diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c index 40f41752c1..c27c646214 100644 --- a/arch/x86/kernel/asm-offsets_64.c +++ b/arch/x86/kernel/asm-offsets_64.c @@ -46,6 +46,9 @@ int main(void) ENTRY(addr_limit); ENTRY(preempt_count); ENTRY(status); +#ifdef CONFIG_IA32_EMULATION + ENTRY(sysenter_return); +#endif BLANK(); #undef ENTRY #define ENTRY(entry) DEFINE(pda_ ## entry, offsetof(struct x8664_pda, entry)) diff --git a/include/asm-x86/thread_info_64.h b/include/asm-x86/thread_info_64.h index 1ac23c1572..c8e7736fc7 100644 --- a/include/asm-x86/thread_info_64.h +++ b/include/asm-x86/thread_info_64.h @@ -33,6 +33,9 @@ struct thread_info { mm_segment_t addr_limit; struct restart_block restart_block; +#ifdef CONFIG_IA32_EMULATION + void __user *sysenter_return; +#endif }; #endif -- 2.39.5