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    SubjectRe: [PATCH v2 3/4] x86: Patch alternatives in the 32-bit vDSO
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    Date
    Am Donnerstag, den 27.02.2014, 16:18 -0800 schrieb Andy Lutomirski:
    > rdtsc_barrier() needs this.
    >

    Thanks for doing this.

    > Signed-off-by: Andy Lutomirski <luto@amacapital.net>
    > ---
    > arch/x86/include/asm/vdso.h | 2 ++
    > arch/x86/vdso/vdso32-setup.c | 25 +++++++++++++------------
    > arch/x86/vdso/vma.c | 9 ++++++---
    > 3 files changed, 21 insertions(+), 15 deletions(-)
    >
    > diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
    > index 6db8b23..a844f90 100644
    > --- a/arch/x86/include/asm/vdso.h
    > +++ b/arch/x86/include/asm/vdso.h
    > @@ -40,4 +40,6 @@ extern const char vdso32_int80_start, vdso32_int80_end;
    > extern const char vdso32_syscall_start, vdso32_syscall_end;
    > extern const char vdso32_sysenter_start, vdso32_sysenter_end;
    >
    > +void __init patch_vdso32(void *vdso, size_t len);
    > +
    > #endif /* _ASM_X86_VDSO_H */
    > diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
    > index 6b74a46..b37aa1d 100644
    > --- a/arch/x86/vdso/vdso32-setup.c
    > +++ b/arch/x86/vdso/vdso32-setup.c
    > @@ -273,29 +273,30 @@ static void map_compat_vdso(int map)
    >
    > int __init sysenter_setup(void)
    > {
    > - void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
    > - const void *vsyscall;
    > - size_t vsyscall_len;
    > + void *vdso_page = (void *)get_zeroed_page(GFP_ATOMIC);
    > + const void *vdso;
    > + size_t vdso_len;
    >
    > - vdso32_pages[0] = virt_to_page(syscall_page);
    > + vdso32_pages[0] = virt_to_page(vdso_page);
    >
    > #ifdef CONFIG_X86_32
    > gate_vma_init();
    > #endif
    >
    > if (vdso32_syscall()) {
    > - vsyscall = &vdso32_syscall_start;
    > - vsyscall_len = &vdso32_syscall_end - &vdso32_syscall_start;
    > + vdso = &vdso32_syscall_start;
    > + vdso_len = &vdso32_syscall_end - &vdso32_syscall_start;
    > } else if (vdso32_sysenter()){
    > - vsyscall = &vdso32_sysenter_start;
    > - vsyscall_len = &vdso32_sysenter_end - &vdso32_sysenter_start;
    > + vdso = &vdso32_sysenter_start;
    > + vdso_len = &vdso32_sysenter_end - &vdso32_sysenter_start;
    > } else {
    > - vsyscall = &vdso32_int80_start;
    > - vsyscall_len = &vdso32_int80_end - &vdso32_int80_start;
    > + vdso = &vdso32_int80_start;
    > + vdso_len = &vdso32_int80_end - &vdso32_int80_start;
    > }
    >
    > - memcpy(syscall_page, vsyscall, vsyscall_len);
    > - relocate_vdso(syscall_page);
    > + memcpy(vdso_page, vdso, vdso_len);
    > + patch_vdso32(vdso_page, vdso_len);
    > + relocate_vdso(vdso_page);
    >
    > return 0;
    > }
    > diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c
    > index 431e875..149caa1 100644
    > --- a/arch/x86/vdso/vma.c
    > +++ b/arch/x86/vdso/vma.c
    > @@ -28,8 +28,11 @@ static unsigned vdso_size;
    > extern char vdsox32_start[], vdsox32_end[];
    > extern struct page *vdsox32_pages[];
    > static unsigned vdsox32_size;
    > +#endif
    >
    > -static void __init patch_vdsox32(void *vdso, size_t len)
    > +#if defined(CONFIG_X86_32) || defined(CONFIG_X86_X32_ABI) || \
    > + defined(CONFIG_COMPAT)
    > +void __init patch_vdso32(void *vdso, size_t len)
    > {
    > Elf32_Ehdr *hdr = vdso;
    > Elf32_Shdr *sechdrs, *alt_sec = 0;
    > @@ -52,7 +55,7 @@ static void __init patch_vdsox32(void *vdso, size_t len)
    > }
    >
    > /* If we get here, it's probably a bug. */
    > - pr_warning("patch_vdsox32: .altinstructions not found\n");
    > + pr_warning("patch_vdso32: .altinstructions not found\n");
    > return; /* nothing to patch */
    >
    > found:
    > @@ -104,7 +107,7 @@ static int __init init_vdso(void)
    > vdso_pages[i] = virt_to_page(vdso_start + i*PAGE_SIZE);
    >
    > #ifdef CONFIG_X86_X32_ABI
    > - patch_vdsox32(vdsox32_start, vdsox32_end - vdsox32_start);
    > + patch_vdso32(vdsox32_start, vdsox32_end - vdsox32_start);
    > npages = (vdsox32_end - vdsox32_start + PAGE_SIZE - 1) / PAGE_SIZE;
    > vdsox32_size = npages << PAGE_SHIFT;
    > for (i = 0; i < npages; i++)




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