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builtins: make sure that flags is setup properly for __clear_cache 

On Linux ARM, the syscall will take 3 arguments (start, end, flags).  Ensure
that we do not pass garbage to the flags, which can cause the cacheflush call to
fail, and therefore cause an abort at runtime.

llvm-svn: 280877
This commit is contained in:
Saleem Abdulrasool 2016-09-07 22:59:54 +00:00
parent 3989c9f96f
commit d14c2c0139
1 changed files with 3 additions and 1 deletions
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4
compiler-rt/lib/builtins/clear_cache.c
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@ -110,10 +110,12 @@ void __clear_cache(void *start, void *end) {
#elif defined(__linux__)
register int start_reg __asm("r0") = (int) (intptr_t) start;
const register int end_reg __asm("r1") = (int) (intptr_t) end;
const register int flags __asm("r2") = 0;
const register int syscall_nr __asm("r7") = __ARM_NR_cacheflush;
__asm __volatile("svc 0x0"
: "=r"(start_reg)
: "r"(syscall_nr), "r"(start_reg), "r"(end_reg));
: "r"(syscall_nr), "r"(start_reg), "r"(end_reg),
"r"(flags));
if (start_reg != 0) {
compilerrt_abort();
}