Samuel Holland 0b1d60d6dd riscv: Fix build with CONFIG_CC_OPTIMIZE_FOR_SIZE=y ... commit 8eb060e101 ("arch/riscv: add Zihintpause support") broke building with CONFIG_CC_OPTIMIZE_FOR_SIZE enabled (gcc 11.1.0): CC arch/riscv/kernel/vdso/vgettimeofday.o In file included from <command-line>: ./arch/riscv/include/asm/jump_label.h: In function 'cpu_relax': ././include/linux/compiler_types.h:285:33: warning: 'asm' operand 0 probably does not match constraints 285 | #define asm_volatile_goto(x...) asm goto(x) | ^~~ ./arch/riscv/include/asm/jump_label.h:41:9: note: in expansion of macro 'asm_volatile_goto' 41 | asm_volatile_goto( | ^~~~~~~~~~~~~~~~~ ././include/linux/compiler_types.h:285:33: error: impossible constraint in 'asm' 285 | #define asm_volatile_goto(x...) asm goto(x) | ^~~ ./arch/riscv/include/asm/jump_label.h:41:9: note: in expansion of macro 'asm_volatile_goto' 41 | asm_volatile_goto( | ^~~~~~~~~~~~~~~~~ make[1]: *** [scripts/Makefile.build:249: arch/riscv/kernel/vdso/vgettimeofday.o] Error 1 make: *** [arch/riscv/Makefile:128: vdso_prepare] Error 2 Having a static branch in cpu_relax() is problematic because that function is widely inlined, including in some quite complex functions like in the VDSO. A quick measurement shows this static branch is responsible by itself for around 40% of the jump table. Drop the static branch, which ends up being the same number of instructions anyway. If Zihintpause is supported, we trade the nop from the static branch for a div. If Zihintpause is unsupported, we trade the jump from the static branch for (what gets interpreted as) a nop. Fixes: 8eb060e101 ("arch/riscv: add Zihintpause support") Signed-off-by: Samuel Holland <samuel@sholland.org> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>		2023-01-31 21:55:27 -08:00
..
boot	RISC-V: Canaan devicetree fixes	2022-08-10 14:43:14 -07:00
configs	riscv: enable Docker requirements in defconfig	2022-07-22 13:43:28 -07:00
errata	riscv: implement Zicbom-based CMO instructions + the t-head variant	2022-08-10 20:49:32 -07:00
include	riscv: Fix build with CONFIG_CC_OPTIMIZE_FOR_SIZE=y	2023-01-31 21:55:27 -08:00
kernel	arch/riscv: add Zihintpause support	2022-08-11 08:03:49 -07:00
kvm	Merge remote-tracking branch 'kvm/next' into kvm-next-5.20	2022-08-01 03:21:00 -04:00
lib	riscv: lib: uaccess: fix CSR_STATUS SR_SUM bit	2022-08-10 14:06:31 -07:00
mm	riscv: implement Zicbom-based CMO instructions + the t-head variant	2022-08-10 20:49:32 -07:00
net	bpf, riscv: Support riscv jit to provide bpf_line_info	2022-06-02 16:26:01 -07:00
purgatory	RISC-V: Add purgatory	2022-05-19 12:18:59 -07:00
Kbuild	riscv: move errata/ and kvm/ builds to arch/riscv/Kbuild	2022-06-01 22:26:32 -07:00
Kconfig	riscv: implement Zicbom-based CMO instructions + the t-head variant	2022-08-10 20:49:32 -07:00
Kconfig.debug
Kconfig.erratas	riscv: implement Zicbom-based CMO instructions + the t-head variant	2022-08-10 20:49:32 -07:00
Kconfig.socs	riscv: Kconfig: Style cleanups	2022-06-30 19:26:16 -07:00
Makefile	arch/riscv: add Zihintpause support	2022-08-11 08:03:49 -07:00