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Subject[PATCH v1 2/3] RISC-V: resort all extensions in consistent orders
Date
From: Conor Dooley <conor.dooley@microchip.com>

Ordering between each and every list of extensions is wildly
inconsistent. Per discussion on the lists pick the following policy:

- The array defining order in /proc/cpuinfo follows a narrow
interpretation of the ISA specifications, described in a comment
immediately presiding it.

- All other lists of extensions are sorted alphabetically.

This will hopefully allow for easier review & future additions, and
reduce conflicts between patchsets as the number of extensions grows.

Link: https://lore.kernel.org/all/20221129144742.2935581-2-conor.dooley@microchip.com/
Suggested-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
I could not decide between adding an alphabetical comment to each
alphabetical site or not. I did it anyway. Scream if you hate it!

I also moved a static branch thingy in this version, but that should not
matter, right? riightt?
---
arch/riscv/include/asm/hwcap.h | 12 +++++++-----
arch/riscv/kernel/cpu.c | 4 ++--
arch/riscv/kernel/cpufeature.c | 6 ++++--
3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index b22525290073..ce522aad641a 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -51,14 +51,15 @@ extern unsigned long elf_hwcap;
* RISCV_ISA_EXT_MAX. 0-25 range is reserved for single letter
* extensions while all the multi-letter extensions should define the next
* available logical extension id.
+ * Entries are sorted alphabetically.
*/
enum riscv_isa_ext_id {
RISCV_ISA_EXT_SSCOFPMF = RISCV_ISA_EXT_BASE,
+ RISCV_ISA_EXT_SSTC,
+ RISCV_ISA_EXT_SVINVAL,
RISCV_ISA_EXT_SVPBMT,
RISCV_ISA_EXT_ZICBOM,
RISCV_ISA_EXT_ZIHINTPAUSE,
- RISCV_ISA_EXT_SSTC,
- RISCV_ISA_EXT_SVINVAL,
RISCV_ISA_EXT_ID_MAX = RISCV_ISA_EXT_MAX,
};

@@ -66,11 +67,12 @@ enum riscv_isa_ext_id {
* This enum represents the logical ID for each RISC-V ISA extension static
* keys. We can use static key to optimize code path if some ISA extensions
* are available.
+ * Entries are sorted alphabetically.
*/
enum riscv_isa_ext_key {
RISCV_ISA_EXT_KEY_FPU, /* For 'F' and 'D' */
- RISCV_ISA_EXT_KEY_ZIHINTPAUSE,
RISCV_ISA_EXT_KEY_SVINVAL,
+ RISCV_ISA_EXT_KEY_ZIHINTPAUSE,
RISCV_ISA_EXT_KEY_MAX,
};

@@ -90,10 +92,10 @@ static __always_inline int riscv_isa_ext2key(int num)
return RISCV_ISA_EXT_KEY_FPU;
case RISCV_ISA_EXT_d:
return RISCV_ISA_EXT_KEY_FPU;
- case RISCV_ISA_EXT_ZIHINTPAUSE:
- return RISCV_ISA_EXT_KEY_ZIHINTPAUSE;
case RISCV_ISA_EXT_SVINVAL:
return RISCV_ISA_EXT_KEY_SVINVAL;
+ case RISCV_ISA_EXT_ZIHINTPAUSE:
+ return RISCV_ISA_EXT_KEY_ZIHINTPAUSE;
default:
return -EINVAL;
}
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
index 68b2bd0cc3bc..686d41b14206 100644
--- a/arch/riscv/kernel/cpu.c
+++ b/arch/riscv/kernel/cpu.c
@@ -161,12 +161,12 @@ device_initcall(riscv_cpuinfo_init);
* New entries to this struct should follow the ordering rules described above.
*/
static struct riscv_isa_ext_data isa_ext_arr[] = {
+ __RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM),
+ __RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),
__RISCV_ISA_EXT_DATA(sscofpmf, RISCV_ISA_EXT_SSCOFPMF),
__RISCV_ISA_EXT_DATA(sstc, RISCV_ISA_EXT_SSTC),
__RISCV_ISA_EXT_DATA(svinval, RISCV_ISA_EXT_SVINVAL),
__RISCV_ISA_EXT_DATA(svpbmt, RISCV_ISA_EXT_SVPBMT),
- __RISCV_ISA_EXT_DATA(zicbom, RISCV_ISA_EXT_ZICBOM),
- __RISCV_ISA_EXT_DATA(zihintpause, RISCV_ISA_EXT_ZIHINTPAUSE),
__RISCV_ISA_EXT_DATA("", RISCV_ISA_EXT_MAX),
};

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 694267d1fe81..8a76a6ce70cf 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -199,12 +199,13 @@ void __init riscv_fill_hwcap(void)
this_hwcap |= isa2hwcap[(unsigned char)(*ext)];
set_bit(*ext - 'a', this_isa);
} else {
+ /* sorted alphabetically */
SET_ISA_EXT_MAP("sscofpmf", RISCV_ISA_EXT_SSCOFPMF);
+ SET_ISA_EXT_MAP("sstc", RISCV_ISA_EXT_SSTC);
+ SET_ISA_EXT_MAP("svinval", RISCV_ISA_EXT_SVINVAL);
SET_ISA_EXT_MAP("svpbmt", RISCV_ISA_EXT_SVPBMT);
SET_ISA_EXT_MAP("zicbom", RISCV_ISA_EXT_ZICBOM);
SET_ISA_EXT_MAP("zihintpause", RISCV_ISA_EXT_ZIHINTPAUSE);
- SET_ISA_EXT_MAP("sstc", RISCV_ISA_EXT_SSTC);
- SET_ISA_EXT_MAP("svinval", RISCV_ISA_EXT_SVINVAL);
}
#undef SET_ISA_EXT_MAP
}
@@ -284,6 +285,7 @@ static bool __init_or_module cpufeature_probe_zicbom(unsigned int stage)
* This code may also be executed before kernel relocation, so we cannot use
* addresses generated by the address-of operator as they won't be valid in
* this context.
+ * Tests, unless otherwise required, are to be added in alphabetical order.
*/
static u32 __init_or_module cpufeature_probe(unsigned int stage)
{
--
2.38.1
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