diff options
Diffstat (limited to 'arch/mips/include/asm/thread_info.h')
| -rw-r--r-- | arch/mips/include/asm/thread_info.h | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h index 4993db40482c..ee26f9a4575d 100644 --- a/arch/mips/include/asm/thread_info.h +++ b/arch/mips/include/asm/thread_info.h @@ -49,8 +49,26 @@ struct thread_info { .addr_limit = KERNEL_DS, \ } -/* How to get the thread information struct from C. */ +/* + * A pointer to the struct thread_info for the currently executing thread is + * held in register $28/$gp. + * + * We declare __current_thread_info as a global register variable rather than a + * local register variable within current_thread_info() because clang doesn't + * support explicit local register variables. + * + * When building the VDSO we take care not to declare the global register + * variable because this causes GCC to not preserve the value of $28/$gp in + * functions that change its value (which is common in the PIC VDSO when + * accessing the GOT). Since the VDSO shouldn't be accessing + * __current_thread_info anyway we declare it extern in order to cause a link + * failure if it's referenced. + */ +#ifdef __VDSO__ +extern struct thread_info *__current_thread_info; +#else register struct thread_info *__current_thread_info __asm__("$28"); +#endif static inline struct thread_info *current_thread_info(void) { |