[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(-)
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;
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/bin...
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;
participants (4)
-
Padmarao.Begari＠microchip.com -
Samuel Holland -
Yu Chien Peter Lin -
Yu-Chien Peter Lin