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| author |   Christophe Leroy <christophe.leroy@csgroup.eu> | 2022-08-18 19:31:25 +0200 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2022-08-22 13:36:59 +1000 |
| commit | 8a8f7866663588b162031a5348c24e42161461cd (patch) | |
| tree | ddfbcd6e478cb0a38aab8eeeab14667d7c1bc5f0 | |
| parent | powerpc/selftests: Use timersub() for gettimeofday() (diff) | |
| download | linux-dev-8a8f7866663588b162031a5348c24e42161461cd.tar.xz linux-dev-8a8f7866663588b162031a5348c24e42161461cd.zip | |
powerpc/vdso: Don't map VDSO at a fixed address on PPC32
PPC64 removed default mapping address from VDSO in
commit 30d0b3682887 ("powerpc: Move 64bit VDSO to improve context
switch performance").
Do like PPC64 and let get_unmapped_area() place the VDSO mapping
at the address it wants, don't force a default address.
This allows randomisation of VDSO address.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/cba76f5a5b01fcc49415e632d92c11c1c5998cab.1660843877.git.christophe.leroy@csgroup.eu
| -rw-r--r-- | arch/powerpc/include/asm/vdso.h | 3 | ||||
| -rw-r--r-- | arch/powerpc/kernel/vdso.c | 13 |
2 files changed, 2 insertions, 14 deletions
diff --git a/arch/powerpc/include/asm/vdso.h b/arch/powerpc/include/asm/vdso.h index 8542e9bbeead..7650b6ce14c8 100644 --- a/arch/powerpc/include/asm/vdso.h +++ b/arch/powerpc/include/asm/vdso.h @@ -2,9 +2,6 @@ #ifndef _ASM_POWERPC_VDSO_H #define _ASM_POWERPC_VDSO_H -/* Default map addresses for 32bit vDSO */ -#define VDSO32_MBASE 0x100000 - #define VDSO_VERSION_STRING LINUX_2.6.15 #ifndef __ASSEMBLY__ diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c index 0da287544054..bf9574ec26ce 100644 --- a/arch/powerpc/kernel/vdso.c +++ b/arch/powerpc/kernel/vdso.c @@ -200,28 +200,19 @@ static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_int if (is_32bit_task()) { vdso_spec = &vdso32_spec; vdso_size = &vdso32_end - &vdso32_start; - vdso_base = VDSO32_MBASE; } else { vdso_spec = &vdso64_spec; vdso_size = &vdso64_end - &vdso64_start; - /* - * On 64bit we don't have a preferred map address. This - * allows get_unmapped_area to find an area near other mmaps - * and most likely share a SLB entry. - */ - vdso_base = 0; } mappings_size = vdso_size + vvar_size; mappings_size += (VDSO_ALIGNMENT - 1) & PAGE_MASK; /* - * pick a base address for the vDSO in process space. We try to put it - * at vdso_base which is the "natural" base for it, but we might fail - * and end up putting it elsewhere. + * Pick a base address for the vDSO in process space. * Add enough to the size so that the result can be aligned. */ - vdso_base = get_unmapped_area(NULL, vdso_base, mappings_size, 0, 0); + vdso_base = get_unmapped_area(NULL, 0, mappings_size, 0, 0); if (IS_ERR_VALUE(vdso_base)) return vdso_base; |