| Message ID | 20221021105905.206385-3-ajones@ventanamicro.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | RISC-V: Ensure Zicbom has a valid block size | expand |
On Fri, Oct 21, 2022 at 12:59:04PM +0200, Andrew Jones wrote: > Currently any isa extension found in the isa string is set in the > isa bitmap. An isa extension set in the bitmap indicates that the > extension is present and may be used (a.k.a is enabled). However, > when an extension cannot be used due to missing dependencies or > errata it should not be added to the bitmap. Introduce a function > where additional checks may be placed in order to determine if an > extension should be enabled or not. > > Note, the checks may simply indicate an issue with the DT, but, > since extensions may be used in early boot, it's not always possible > to simply produce an error at the point the issue is determined. > It's best to keep the extension disabled and produce an error. Aye, agreed. Could be pretty nasty chasing down something like this... Reviewed-by: Conor Dooley <conor.dooley@microchip.com> > > No functional change intended, as the function is only introduced > and always returns true. A later patch will provide checks for an > isa extension. > > Signed-off-by: Andrew Jones <ajones@ventanamicro.com> > --- > arch/riscv/kernel/cpufeature.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c > index 4677320d7e31..220be7222129 100644 > --- a/arch/riscv/kernel/cpufeature.c > +++ b/arch/riscv/kernel/cpufeature.c > @@ -68,6 +68,11 @@ bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit) > } > EXPORT_SYMBOL_GPL(__riscv_isa_extension_available); > > +static bool riscv_isa_extension_check(int id) > +{ > + return true; > +} > + > void __init riscv_fill_hwcap(void) > { > struct device_node *node; > @@ -189,7 +194,8 @@ void __init riscv_fill_hwcap(void) > #define SET_ISA_EXT_MAP(name, bit) \ > do { \ > if ((ext_end - ext == sizeof(name) - 1) && \ > - !memcmp(ext, name, sizeof(name) - 1)) \ > + !memcmp(ext, name, sizeof(name) - 1) && \ > + riscv_isa_extension_check(bit)) \ > set_bit(bit, this_isa); \ > } while (false) \ > > @@ -198,8 +204,10 @@ void __init riscv_fill_hwcap(void) > if (!ext_long) { > int nr = *ext - 'a'; > > - this_hwcap |= isa2hwcap[nr]; > - set_bit(nr, this_isa); > + if (riscv_isa_extension_check(nr)) { > + 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); > -- > 2.37.3 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 4677320d7e31..220be7222129 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -68,6 +68,11 @@ bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit) } EXPORT_SYMBOL_GPL(__riscv_isa_extension_available); +static bool riscv_isa_extension_check(int id) +{ + return true; +} + void __init riscv_fill_hwcap(void) { struct device_node *node; @@ -189,7 +194,8 @@ void __init riscv_fill_hwcap(void) #define SET_ISA_EXT_MAP(name, bit) \ do { \ if ((ext_end - ext == sizeof(name) - 1) && \ - !memcmp(ext, name, sizeof(name) - 1)) \ + !memcmp(ext, name, sizeof(name) - 1) && \ + riscv_isa_extension_check(bit)) \ set_bit(bit, this_isa); \ } while (false) \ @@ -198,8 +204,10 @@ void __init riscv_fill_hwcap(void) if (!ext_long) { int nr = *ext - 'a'; - this_hwcap |= isa2hwcap[nr]; - set_bit(nr, this_isa); + if (riscv_isa_extension_check(nr)) { + 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);
Currently any isa extension found in the isa string is set in the isa bitmap. An isa extension set in the bitmap indicates that the extension is present and may be used (a.k.a is enabled). However, when an extension cannot be used due to missing dependencies or errata it should not be added to the bitmap. Introduce a function where additional checks may be placed in order to determine if an extension should be enabled or not. Note, the checks may simply indicate an issue with the DT, but, since extensions may be used in early boot, it's not always possible to simply produce an error at the point the issue is determined. It's best to keep the extension disabled and produce an error. No functional change intended, as the function is only introduced and always returns true. A later patch will provide checks for an isa extension. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> --- arch/riscv/kernel/cpufeature.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)