@@ -7,6 +7,7 @@
*/
#include <linux/bitmap.h>
+#include <linux/ctype.h>
#include <linux/of.h>
#include <asm/processor.h>
#include <asm/hwcap.h>
@@ -66,7 +67,7 @@ void __init riscv_fill_hwcap(void)
struct device_node *node;
const char *isa;
char print_str[NUM_ALPHA_EXTS + 1];
- size_t i, j, isa_len;
+ int i, j;
static unsigned long isa2hwcap[256] = {0};
isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
@@ -92,23 +93,59 @@ void __init riscv_fill_hwcap(void)
continue;
}
- i = 0;
- isa_len = strlen(isa);
#if IS_ENABLED(CONFIG_32BIT)
if (!strncmp(isa, "rv32", 4))
- i += 4;
+ isa += 4;
#elif IS_ENABLED(CONFIG_64BIT)
if (!strncmp(isa, "rv64", 4))
- i += 4;
+ isa += 4;
#endif
- for (; i < isa_len; ++i) {
- this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
+ for (; *isa; ++isa) {
+ const char *ext = isa++;
+ bool ext_long, ext_err = false;
+
+ switch (*ext) {
+ case 's':
+ case 'x':
+ case 'z':
+ ext_long = true;
+ /* Multi-letter extension must be delimited */
+ for (; *isa && *isa != '_'; ++isa)
+ if (!islower(*isa) && !isdigit(*isa))
+ ext_err = true;
+ /* ... but must be ignored. */
+ break;
+ default:
+ ext_long = false;
+ if (!islower(*ext)) {
+ ext_err = true;
+ break;
+ }
+ /* Find next extension */
+ if (!isdigit(*isa))
+ break;
+ while (isdigit(*++isa))
+ ;
+ if (*isa != 'p')
+ break;
+ if (!isdigit(*++isa)) {
+ --isa;
+ break;
+ }
+ while (isdigit(*++isa))
+ ;
+ break;
+ }
+ if (*isa != '_')
+ --isa;
/*
- * TODO: X, Y and Z extension parsing for Host ISA
- * bitmap will be added in-future.
+ * TODO: Full version-aware handling including
+ * multi-letter extensions will be added in-future.
*/
- if ('a' <= isa[i] && isa[i] < 'x')
- this_isa |= (1UL << (isa[i] - 'a'));
+ if (ext_err || ext_long)
+ continue;
+ this_hwcap |= isa2hwcap[(unsigned char)(*ext)];
+ this_isa |= (1UL << (*ext - 'a'));
}
/*
Current hart ISA ("riscv,isa") parser don't correctly parse: 1. Multi-letter extensions 2. Version numbers If we don't have those in "riscv,isa", that's fine. However, many of standardized multi-letter extensions are being frozen and ratified. The current "riscv,isa" parser that is easily confused by multi-letter extensions and "p" in version numbers can be a huge problem for adding new extensions through the device tree. Leaving it would create incompatible hacks and would make "riscv,isa" value unreliable. This commit implements minimal parser for "riscv,isa" strings. With this, we can safely ignore multi-letter extensions and version numbers. Important Note: This commit does handle "H" as a single-letter extension. This handling is not compliant with current version of RISC-V ISA Manual but will going to be in a few months. Signed-off-by: Tsukasa OI <research_trasio@irq.a4lg.com> --- arch/riscv/kernel/cpufeature.c | 59 +++++++++++++++++++++++++++------- 1 file changed, 48 insertions(+), 11 deletions(-)