diff options
| author | Kevin Brodsky <kevin.brodsky@arm.com> | 2016-11-23 14:01:10 +0000 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2019-12-23 23:43:38 +0200 |
| commit | 2b1b26535c603cdb2b31ef71f16d9bfd1a461aad (patch) | |
| tree | b057df2d9e49c85831efb777b116aef9a42b53f4 /arch/arm64/include/asm/processor.h | |
| parent | 3a1d14f58f520b8c02e4475c714af3fa72c75c3e (diff) | |
FROMLIST: [PATCH v2 1/3] arm64: compat: Split the sigreturn trampolines and kuser helpers (C sources)
(cherry picked from url http://lkml.iu.edu/hypermail/linux/kernel/1709.1/01901.html)
AArch32 processes are currently installed a special [vectors] page that
contains the sigreturn trampolines and the kuser helpers, at the fixed
address mandated by the kuser helpers ABI.
Having both functionalities in the same page has become problematic,
because:
* It makes it impossible to disable the kuser helpers (the sigreturn
trampolines cannot be removed), which is possible on arm.
* A future 32-bit vDSO would provide the sigreturn trampolines itself,
making those in [vectors] redundant.
This patch addresses the problem by moving the sigreturn trampolines to
a separate [sigpage] page, mirroring [sigpage] on arm.
Even though [vectors] has always been a misnomer on arm64/compat, as
there is no AArch32 vector there (and now only the kuser helpers),
its name has been left unchanged, for compatibility with arm (there
are reports of software relying on [vectors] being there as the last
mapping in /proc/maps).
mm->context.vdso used to point to the [vectors] page, which is
unnecessary (as its address is fixed). It now points to the [sigpage]
page (whose address is randomized like a vDSO).
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Bug: 9674955
Bug: 63737556
Bug: 20045882
Change-Id: I52a56ea71d7326df8c784f90eb73b5c324fe9d20
Diffstat (limited to 'arch/arm64/include/asm/processor.h')
| -rw-r--r-- | arch/arm64/include/asm/processor.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index a0053d23b35a..7766635158df 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -40,9 +40,9 @@ #ifdef __KERNEL__ #define STACK_TOP_MAX TASK_SIZE_64 #ifdef CONFIG_COMPAT -#define AARCH32_VECTORS_BASE 0xffff0000 +#define AARCH32_KUSER_HELPERS_BASE 0xffff0000 #define STACK_TOP (test_thread_flag(TIF_32BIT) ? \ - AARCH32_VECTORS_BASE : STACK_TOP_MAX) + AARCH32_KUSER_HELPERS_BASE : STACK_TOP_MAX) #else #define STACK_TOP STACK_TOP_MAX #endif /* CONFIG_COMPAT */ |