MIPS: mipsregs.h: Make read_c0_prid use const accessor
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Web: https://git.kernel.org/torvalds/c/6538953f1e1f8001efde1cee8eb61f5ef8ec7b5d Commit: 6538953f1e1f8001efde1cee8eb61f5ef8ec7b5d Parent: cd1e0737efcaa0889810216cb01017d97f83c5e0 Refname: refs/heads/master Author: James Hogan <[email protected]> AuthorDate: Mon Dec 11 16:13:15 2017 +0000 Committer: James Hogan <[email protected]> CommitDate: Tue Jan 9 22:26:45 2018 +0000 MIPS: mipsregs.h: Make read_c0_prid use const accessor Make read_c0_prid() use the new constant accessor macros so that it can potentially be optimised or removed by the compiler. This is particularly important under virtualisation, where even with hardware assisted virtualisation (VZ), access to the PRid register may need to be emulated by the hypervisor. In particular this helps eliminate the read of the PRid register in the rather frequently called add_interrupt_randomness() (which calls into arch/mips/include/asm/timex.h) when the prid is unused but the read can't be removed due to the inline asm being marked __volatile__. Reported-by: Yann LeDu <[email protected]> Signed-off-by: James Hogan <[email protected]> Cc: Ralf Baechle <[email protected]> Cc: Maciej W. Rozycki <[email protected]> Cc: [email protected] Patchwork: https://patchwork.linux-mips.org/patch/17923/ --- arch/mips/include/asm/mipsregs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h index 9c409f2d89e6..7a59ad6e7f7d 100644 --- a/arch/mips/include/asm/mipsregs.h +++ b/arch/mips/include/asm/mipsregs.h @@ -1558,7 +1558,7 @@ do { \ #define read_c0_epc() __read_ulong_c0_register($14, 0) #define write_c0_epc(val) __write_ulong_c0_register($14, 0, val) -#define read_c0_prid() __read_32bit_c0_register($15, 0) +#define read_c0_prid() __read_const_32bit_c0_register($15, 0) #define read_c0_cmgcrbase() __read_ulong_c0_register($15, 3) -- To unsubscribe from this list: send the line "unsubscribe git-commits-head" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html