diff options
| author | Gabriel Krisman Bertazi <krisman@collabora.com> | 2020-10-03 23:25:35 -0400 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-10-26 13:46:47 +0100 |
| commit | ff170cd0595398a7b66cb40f249eb2f10c29b66d (patch) | |
| tree | aaea8a15b4b7675f326d2cf8936e67fce26fd5f3 /arch/x86/include/asm/mmu.h | |
| parent | 3316ec8ccd34e19690a12e65801d605d25155031 (diff) | |
| download | linux-next-ff170cd0595398a7b66cb40f249eb2f10c29b66d.tar.gz | |
x86/mm: Convert mmu context ia32_compat into a proper flags field
The ia32_compat attribute is a weird thing. It mirrors TIF_IA32 and
TIF_X32 and is used only in two very unrelated places: (1) to decide if
the vsyscall page is accessible (2) for uprobes to find whether the
patched instruction is 32 or 64 bit.
In preparation to remove the TIF flags, a new mechanism is required for
ia32_compat, but given its odd semantics, adding a real flags field which
configures these specific behaviours is the best option.
So, set_personality_x64() can ask for the vsyscall page, which is not
available in x32/ia32 and set_personality_ia32() can configure the uprobe
code as needed.
uprobe cannot rely on other methods like user_64bit_mode() to decide how
to patch, so it needs some specific flag like this.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski<luto@kernel.org>
Link: https://lore.kernel.org/r/20201004032536.1229030-10-krisman@collabora.com
Diffstat (limited to 'arch/x86/include/asm/mmu.h')
| -rw-r--r-- | arch/x86/include/asm/mmu.h | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h index 9257667d13c5..5d7494631ea9 100644 --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -6,6 +6,12 @@ #include <linux/rwsem.h> #include <linux/mutex.h> #include <linux/atomic.h> +#include <linux/bits.h> + +/* Uprobes on this MM assume 32-bit code */ +#define MM_CONTEXT_UPROBE_IA32 BIT(0) +/* vsyscall page is accessible on this MM */ +#define MM_CONTEXT_HAS_VSYSCALL BIT(1) /* * x86 has arch-specific MMU state beyond what lives in mm_struct. @@ -33,8 +39,7 @@ typedef struct { #endif #ifdef CONFIG_X86_64 - /* True if mm supports a task running in 32 bit compatibility mode. */ - unsigned short ia32_compat; + unsigned short flags; #endif struct mutex lock; |