Unverified Commit 72685554 authored by Andrew Jones's avatar Andrew Jones Committed by Palmer Dabbelt
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RISC-V: Improve use of isa2hwcap[] 



Improve isa2hwcap[] by removing it from static storage, as
riscv_fill_hwcap() is only called once, and by reducing its size
from 256 bytes to 26. The latter improvement is possible because
isa2hwcap[] will never be indexed with capital letters and we can
precompute the offsets from 'a'.

No functional change intended.

Signed-off-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Reviewed-by: default avatarConor Dooley <conor.dooley@microchip.com>
Reviewed-by: default avatarHeiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20221129143447.49714-2-ajones@ventanamicro.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 5c20a3a9

arch/riscv/kernel/cpufeature.c

+11 −9
Original line number Diff line number Diff line
@@ -74,15 +74,15 @@ void __init riscv_fill_hwcap(void) 
	const char *isa;

	char print_str[NUM_ALPHA_EXTS + 1];

	int i, j, rc;

	static unsigned long isa2hwcap[256] = {0};

	unsigned long isa2hwcap[26] = {0};

	unsigned long hartid;



	isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;

	isa2hwcap['m'] = isa2hwcap['M'] = COMPAT_HWCAP_ISA_M;

	isa2hwcap['a'] = isa2hwcap['A'] = COMPAT_HWCAP_ISA_A;

	isa2hwcap['f'] = isa2hwcap['F'] = COMPAT_HWCAP_ISA_F;

	isa2hwcap['d'] = isa2hwcap['D'] = COMPAT_HWCAP_ISA_D;

	isa2hwcap['c'] = isa2hwcap['C'] = COMPAT_HWCAP_ISA_C;

	isa2hwcap['i' - 'a'] = COMPAT_HWCAP_ISA_I;

	isa2hwcap['m' - 'a'] = COMPAT_HWCAP_ISA_M;

	isa2hwcap['a' - 'a'] = COMPAT_HWCAP_ISA_A;

	isa2hwcap['f' - 'a'] = COMPAT_HWCAP_ISA_F;

	isa2hwcap['d' - 'a'] = COMPAT_HWCAP_ISA_D;

	isa2hwcap['c' - 'a'] = COMPAT_HWCAP_ISA_C;



	elf_hwcap = 0;
@@ -196,8 +196,10 @@ void __init riscv_fill_hwcap(void) 
			if (unlikely(ext_err))

				continue;

			if (!ext_long) {

				this_hwcap |= isa2hwcap[(unsigned char)(*ext)];

				set_bit(*ext - 'a', this_isa);

				int nr = *ext - 'a';



				this_hwcap |= isa2hwcap[nr];

				set_bit(nr, this_isa);

			} else {

				SET_ISA_EXT_MAP("sscofpmf", RISCV_ISA_EXT_SSCOFPMF);

				SET_ISA_EXT_MAP("svpbmt", RISCV_ISA_EXT_SVPBMT);