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arm64: Remove the get_thread_info() function 

This function was introduced by previous commits implementing UAO.
However, it can be replaced with task_thread_info() in
uao_thread_switch() or get_fs() in do_page_fault() (the latter being
called only on the current context, so no need for using the saved
pt_regs).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Catalin Marinas 2016-02-18 15:50:04 +00:00
parent 7054419600
commit e950631e84
3 changed files with 7 additions and 16 deletions
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6
arch/arm64/include/asm/thread_info.h
View File

@ -85,12 +85,6 @@ static inline struct thread_info *current_thread_info(void)
return (struct thread_info *)sp_el0;
}
/* Access struct thread_info of another thread */
static inline struct thread_info *get_thread_info(unsigned long thread_stack)
{
return (struct thread_info *)(thread_stack & ~(THREAD_SIZE - 1));
}
#define thread_saved_pc(tsk) \
((unsigned long)(tsk->thread.cpu_context.pc))
#define thread_saved_sp(tsk) \

15
arch/arm64/kernel/process.c
View File

@ -315,15 +315,12 @@ static void tls_thread_switch(struct task_struct *next)
/* Restore the UAO state depending on next's addr_limit */
static void uao_thread_switch(struct task_struct *next)
{
unsigned long next_sp = next->thread.cpu_context.sp;
if (IS_ENABLED(CONFIG_ARM64_UAO) &&
get_thread_info(next_sp)->addr_limit == KERNEL_DS)
asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO,
CONFIG_ARM64_UAO));
else
asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO,
CONFIG_ARM64_UAO));
if (IS_ENABLED(CONFIG_ARM64_UAO)) {
if (task_thread_info(next)->addr_limit == KERNEL_DS)
asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO));
else
asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO));
}
}
/*

2
arch/arm64/mm/fault.c
View File

@ -234,7 +234,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
}
if (permission_fault(esr) && (addr < USER_DS)) {
if (get_thread_info(regs->sp)->addr_limit == KERNEL_DS)
if (get_fs() == KERNEL_DS)
panic("Accessing user space memory with fs=KERNEL_DS");
if (!search_exception_tables(regs->pc))