| Message ID | 20221105060214.2526-1-peterlin@andestech.com |
|---|---|
| State | Accepted |
| Commit | c277c787a09254ebdf919c7cfc94631fe854677d |
| Delegated to: | Andes |
| Headers | show |
| Series | [v2] riscv: Fix detecting FPU support in standard extension | expand |
> From: U-Boot <u-boot-bounces@lists.denx.de> On Behalf Of Yu Chien Peter Lin > Sent: Saturday, November 05, 2022 2:02 PM > To: u-boot@lists.denx.de > Cc: samuel@sholland.org; Peter Yu-Chien Lin(林宇謙) <peterlin@andestech.com> > Subject: [PATCH v2] riscv: Fix detecting FPU support in standard extension > > We should check the string until it hits underscore, in case it searches for the letters in the custom extension. For example, "rv64imac_xandes" will be treated as D extension support since there is a "d" in "andes", resulting illegal instruction caused by initializing FCSR. > > Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com> > --- > arch/riscv/cpu/cpu.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) Reviewed-by: Rick Chen <rick@andestech.com>
> On Sat, 2022-11-05 at 14:02 +0800, Yu Chien Peter Lin wrote: > > We should check the string until it hits underscore, in case it > searches for the letters in the custom extension. For example, > "rv64imac_xandes" will be treated as D extension support since > there is a "d" in "andes", resulting illegal instruction caused > by initializing FCSR. > > Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com> > --- > arch/riscv/cpu/cpu.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c > index 52ab02519f..d34c8efce0 100644 > --- a/arch/riscv/cpu/cpu.c > +++ b/arch/riscv/cpu/cpu.c > @@ -36,6 +36,7 @@ static inline bool supports_extension(char ext) > #ifdef CONFIG_CPU > struct udevice *dev; > char desc[32]; > + int i; > > uclass_find_first_device(UCLASS_CPU, &dev); > if (!dev) { > @@ -43,9 +44,16 @@ static inline bool supports_extension(char ext) > return false; > } > if (!cpu_get_desc(dev, desc, sizeof(desc))) { > - /* skip the first 4 characters (rv32|rv64) */ > - if (strchr(desc + 4, ext)) > - return true; > + /* > + * skip the first 4 characters (rv32|rv64) and > + * check until underscore > + */ > + for (i = 4; i < sizeof(desc); i++) { > + if (desc[i] == '_' || desc[i] == '\0') > + break; > + if (desc[i] == ext) > + return true; > + } > Reviewed-by: Padmarao Begari <padmarao.begari@microchip.com> > } > > return false; > -- > 2.34.1 >
On 11/5/22 01:02, Yu Chien Peter Lin wrote: > We should check the string until it hits underscore, in case it > searches for the letters in the custom extension. For example, > "rv64imac_xandes" will be treated as D extension support since > there is a "d" in "andes", resulting illegal instruction caused > by initializing FCSR. > > Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com> > --- > arch/riscv/cpu/cpu.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c > index 52ab02519f..d34c8efce0 100644 > --- a/arch/riscv/cpu/cpu.c > +++ b/arch/riscv/cpu/cpu.c > @@ -36,6 +36,7 @@ static inline bool supports_extension(char ext) > #ifdef CONFIG_CPU > struct udevice *dev; > char desc[32]; > + int i; > > uclass_find_first_device(UCLASS_CPU, &dev); > if (!dev) { > @@ -43,9 +44,16 @@ static inline bool supports_extension(char ext) > return false; > } > if (!cpu_get_desc(dev, desc, sizeof(desc))) { > - /* skip the first 4 characters (rv32|rv64) */ > - if (strchr(desc + 4, ext)) > - return true; > + /* > + * skip the first 4 characters (rv32|rv64) and > + * check until underscore > + */ This probably works for the intended usage, but it is not guaranteed to work. Underscores are allowed even between single-letter extensions. See section 29.5 ("Underscores") of the unprivileged spec. Still, this is an improvement, so: Reviewed-by: Samuel Holland <samuel@sholland.org> > + for (i = 4; i < sizeof(desc); i++) { > + if (desc[i] == '_' || desc[i] == '\0') > + break; > + if (desc[i] == ext) > + return true; > + } > } > > return false;
On Sun, Nov 13, 2022 at 03:47:38PM -0600, Samuel Holland wrote: > On 11/5/22 01:02, Yu Chien Peter Lin wrote: > > We should check the string until it hits underscore, in case it > > searches for the letters in the custom extension. For example, > > "rv64imac_xandes" will be treated as D extension support since > > there is a "d" in "andes", resulting illegal instruction caused > > by initializing FCSR. > > > > Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com> > > --- > > arch/riscv/cpu/cpu.c | 14 +++++++++++--- > > 1 file changed, 11 insertions(+), 3 deletions(-) > > > > diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c > > index 52ab02519f..d34c8efce0 100644 > > --- a/arch/riscv/cpu/cpu.c > > +++ b/arch/riscv/cpu/cpu.c > > @@ -36,6 +36,7 @@ static inline bool supports_extension(char ext) > > #ifdef CONFIG_CPU > > struct udevice *dev; > > char desc[32]; > > + int i; > > > > uclass_find_first_device(UCLASS_CPU, &dev); > > if (!dev) { > > @@ -43,9 +44,16 @@ static inline bool supports_extension(char ext) > > return false; > > } > > if (!cpu_get_desc(dev, desc, sizeof(desc))) { > > - /* skip the first 4 characters (rv32|rv64) */ > > - if (strchr(desc + 4, ext)) > > - return true; > > + /* > > + * skip the first 4 characters (rv32|rv64) and > > + * check until underscore > > + */ > > This probably works for the intended usage, but it is not guaranteed to > work. Underscores are allowed even between single-letter extensions. See > section 29.5 ("Underscores") of the unprivileged spec. Still, this is an > improvement, so: > > Reviewed-by: Samuel Holland <samuel@sholland.org> Aah, I missed that case. I supposed the strings always match the pattern stated in riscv cpus binding [1], the detection logic here needs to be updated once the case is also allowed. [1] https://github.com/torvalds/linux/blob/v6.1-rc5/Documentation/devicetree/bindings/riscv/cpus.yaml#L83 Thanks for your review! Best regards, Peter Lin > > > + for (i = 4; i < sizeof(desc); i++) { > > + if (desc[i] == '_' || desc[i] == '\0') > > + break; > > + if (desc[i] == ext) > > + return true; > > + } > > } > > > > return false; >
diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c index 52ab02519f..d34c8efce0 100644 --- a/arch/riscv/cpu/cpu.c +++ b/arch/riscv/cpu/cpu.c @@ -36,6 +36,7 @@ static inline bool supports_extension(char ext) #ifdef CONFIG_CPU struct udevice *dev; char desc[32]; + int i; uclass_find_first_device(UCLASS_CPU, &dev); if (!dev) { @@ -43,9 +44,16 @@ static inline bool supports_extension(char ext) return false; } if (!cpu_get_desc(dev, desc, sizeof(desc))) { - /* skip the first 4 characters (rv32|rv64) */ - if (strchr(desc + 4, ext)) - return true; + /* + * skip the first 4 characters (rv32|rv64) and + * check until underscore + */ + for (i = 4; i < sizeof(desc); i++) { + if (desc[i] == '_' || desc[i] == '\0') + break; + if (desc[i] == ext) + return true; + } } return false;
We should check the string until it hits underscore, in case it searches for the letters in the custom extension. For example, "rv64imac_xandes" will be treated as D extension support since there is a "d" in "andes", resulting illegal instruction caused by initializing FCSR. Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com> --- arch/riscv/cpu/cpu.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)