Linus Torvalds a959dc88f9 Use __put_user_goto in __put_user_size() and unsafe_put_user() ... This actually enables the __put_user_goto() functionality in unsafe_put_user(). For an example of the effect of this, this is the code generated for the unsafe_put_user(signo, &infop->si_signo, Efault); in the waitid() system call: movl %ecx,(%rbx) # signo, MEM[(struct __large_struct *)_2] It's just one single store instruction, along with generating an exception table entry pointing to the Efault label case in case that instruction faults. Before, we would generate this: xorl %edx, %edx movl %ecx,(%rbx) # signo, MEM[(struct __large_struct *)_3] testl %edx, %edx jne .L309 with the exception table generated for that 'mov' instruction causing us to jump to a stub that set %edx to -EFAULT and then jumped back to the 'testl' instruction. So not only do we now get rid of the extra code in the normal sequence, we also avoid unnecessarily keeping that extra error register live across it all. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2019-01-04 18:15:25 -08:00
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asm	Use __put_user_goto in __put_user_size() and unsafe_put_user()	2019-01-04 18:15:25 -08:00
uapi/asm	x86/acpi, x86/boot: Take RSDP address from boot params if available	2018-11-20 09:43:11 +01:00