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author | 2023-03-12 14:25:57 +0300 | |
---|---|---|
committer | 2023-03-16 13:08:39 -0700 | |
commit | 5ef495e55f07aa117fdd8e187c9901cefc02fe0a (patch) | |
tree | 796fe02adece943b5b149acbd00f9d327a821596 /arch/x86 | |
parent | x86/mm: Rework address range check in get_user() and put_user() (diff) | |
download | linux-5ef495e55f07aa117fdd8e187c9901cefc02fe0a.tar.gz linux-5ef495e55f07aa117fdd8e187c9901cefc02fe0a.tar.bz2 linux-5ef495e55f07aa117fdd8e187c9901cefc02fe0a.zip |
x86: Allow atomic MM_CONTEXT flags setting
So far there's no need in atomic setting of MM context flags in
mm_context_t::flags. The flags set early in exec and never change
after that.
LAM enabling requires atomic flag setting. The upcoming flag
MM_CONTEXT_FORCE_TAGGED_SVA can be set much later in the process
lifetime where multiple threads exist.
Convert the field to unsigned long and do MM_CONTEXT_* accesses with
__set_bit() and test_bit().
No functional changes.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-3-kirill.shutemov%40linux.intel.com
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/entry/vsyscall/vsyscall_64.c | 2 | ||||
-rw-r--r-- | arch/x86/include/asm/mmu.h | 6 | ||||
-rw-r--r-- | arch/x86/include/asm/mmu_context.h | 2 | ||||
-rw-r--r-- | arch/x86/kernel/process_64.c | 4 |
4 files changed, 7 insertions, 7 deletions
diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c index d234ca797e4a..e0ca8120aea8 100644 --- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -317,7 +317,7 @@ static struct vm_area_struct gate_vma __ro_after_init = { struct vm_area_struct *get_gate_vma(struct mm_struct *mm) { #ifdef CONFIG_COMPAT - if (!mm || !(mm->context.flags & MM_CONTEXT_HAS_VSYSCALL)) + if (!mm || !test_bit(MM_CONTEXT_HAS_VSYSCALL, &mm->context.flags)) return NULL; #endif if (vsyscall_mode == NONE) diff --git a/arch/x86/include/asm/mmu.h b/arch/x86/include/asm/mmu.h index 5d7494631ea9..efa3eaee522c 100644 --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -9,9 +9,9 @@ #include <linux/bits.h> /* Uprobes on this MM assume 32-bit code */ -#define MM_CONTEXT_UPROBE_IA32 BIT(0) +#define MM_CONTEXT_UPROBE_IA32 0 /* vsyscall page is accessible on this MM */ -#define MM_CONTEXT_HAS_VSYSCALL BIT(1) +#define MM_CONTEXT_HAS_VSYSCALL 1 /* * x86 has arch-specific MMU state beyond what lives in mm_struct. @@ -39,7 +39,7 @@ typedef struct { #endif #ifdef CONFIG_X86_64 - unsigned short flags; + unsigned long flags; #endif struct mutex lock; diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index e01aa74a6de7..b4e4a0c04304 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -182,7 +182,7 @@ static inline void arch_exit_mmap(struct mm_struct *mm) static inline bool is_64bit_mm(struct mm_struct *mm) { return !IS_ENABLED(CONFIG_IA32_EMULATION) || - !(mm->context.flags & MM_CONTEXT_UPROBE_IA32); + !test_bit(MM_CONTEXT_UPROBE_IA32, &mm->context.flags); } #else static inline bool is_64bit_mm(struct mm_struct *mm) diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index bb65a68b4b49..cd34bcf7f860 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -671,7 +671,7 @@ void set_personality_64bit(void) task_pt_regs(current)->orig_ax = __NR_execve; current_thread_info()->status &= ~TS_COMPAT; if (current->mm) - current->mm->context.flags = MM_CONTEXT_HAS_VSYSCALL; + __set_bit(MM_CONTEXT_HAS_VSYSCALL, ¤t->mm->context.flags); /* TBD: overwrites user setup. Should have two bits. But 64bit processes have always behaved this way, @@ -708,7 +708,7 @@ static void __set_personality_ia32(void) * uprobes applied to this MM need to know this and * cannot use user_64bit_mode() at that time. */ - current->mm->context.flags = MM_CONTEXT_UPROBE_IA32; + __set_bit(MM_CONTEXT_UPROBE_IA32, ¤t->mm->context.flags); } current->personality |= force_personality32; |