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kernel: init: use C implementation for STACK_CANARY_INIT

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Due to a limitation on XCC, the inline assembly does not
produce the expected instructions. This results in a wrong
code sequence. On the other hand, plain C code works well.
The note about compilers seems to not be an issue on any of
our currently supported compilers.

Change-Id: I9d2ab0fbf8a48d9dad51da3fd54453f205516d74
Signed-off-by: Mazen NEIFER <mazen@nestwave.com>
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Mazen NEIFER 2017-02-07 10:01:12 +01:00 committed by Andrew Boie
parent e67828ba20
commit e2bbad9600
1 changed files with 4 additions and 43 deletions
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47
kernel/init.c
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@ -321,48 +321,8 @@ static void switch_to_main_thread(void)
}
#ifdef CONFIG_STACK_CANARIES
/**
*
* @brief Initialize the kernel's stack canary
*
* This macro initializes the kernel's stack canary global variable,
* __stack_chk_guard, with a random value.
*
* INTERNAL
* Depending upon the compiler, modifying __stack_chk_guard directly at runtime
* may generate a build error. In-line assembly is used as a workaround.
*/
extern void *__stack_chk_guard;
#if defined(CONFIG_X86)
#define _MOVE_INSTR "movl %1, %0"
#define _MOVE_MEM "=m"
#elif defined(CONFIG_ARM)
#define _MOVE_INSTR "str %1, %0"
#define _MOVE_MEM "=m"
#elif defined(CONFIG_ARC)
#define _MOVE_INSTR "st %1, %0"
#define _MOVE_MEM "=m"
#elif defined(CONFIG_RISCV32)
#define _MOVE_INSTR "sw %1, 0x00(%0)"
#define _MOVE_MEM "=r"
#else
#error "Unknown Architecture type"
#endif /* CONFIG_X86 */
#define STACK_CANARY_INIT() \
do { \
register void *tmp; \
tmp = (void *)sys_rand32_get(); \
__asm__ volatile(_MOVE_INSTR ";\n\t" \
: _MOVE_MEM(__stack_chk_guard) \
: "r"(tmp)); \
} while (0)
#else /* !CONFIG_STACK_CANARIES */
#define STACK_CANARY_INIT()
#endif /* CONFIG_STACK_CANARIES */
#endif
/**
*
@ -401,8 +361,9 @@ FUNC_NORETURN void _Cstart(void)
_sys_device_do_config_level(_SYS_INIT_LEVEL_PRE_KERNEL_2);
/* initialize stack canaries */
STACK_CANARY_INIT();
#ifdef CONFIG_STACK_CANARIES
__stack_chk_guard = (void *)sys_rand32_get();
#endif
/* display boot banner */