From: Conor Dooley <conor.doo...@microchip.com>
The first multi-letter extension after the single-letter extensions does
not have to be preceded by an underscore, which could cause the parser
to mistakenly find a single-letter extension after the start of the
multi-letter portion of the string.
Three letters precede multi-letter extensions (s, x & z), none of which
are valid single-letter extensions. The dt-binding also allows
multi-letter extensions starting with h, but no such extension have been
frozen or ratified, and the unprivileged spec no longer uses "h" as a
prefix for multi-letter hypervisor extensions, having moved to "sh"
instead. For that reason, modify the parser to stop at s, x & z to prevent
this overrun, ignoring h.
Signed-off-by: Conor Dooley <conor.doo...@microchip.com>
---
The parser in U-Boot only supports single-letter extensions & the
single-letter h has to be at the end of the single-letter section, so it
would not be difficult to terminate parsing once a h is seen (you'd need
to support the hypervisor extension to support additional hypervisor
extensions after all) if in the future a multi-letter extension starting
with h did come about. I've got no problem adding a special case for h,
but I'm tempted to just remove the multi-letter h extensions from the
binding, given there's actually not going to be any extensions ratified
using that naming scheme.
CC: Rick Chen <r...@andestech.com>
CC: Leo <ycli...@andestech.com>
CC: Tom Rini <tr...@konsulko.com>
CC: Simon Glass <s...@chromium.org>
CC: Chanho Park <chanho61.p...@samsung.com>
CC: Heinrich Schuchardt <xypron.g...@gmx.de>
CC: Bin Meng <bmeng...@gmail.com>
CC: Conor Dooley <conor.doo...@microchip.com>
CC: pal...@dabbelt.com
CC: u-boot@lists.denx.de
---
arch/riscv/cpu/cpu.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c
index 8445c5823e..ecfefa1a02 100644
--- a/arch/riscv/cpu/cpu.c
+++ b/arch/riscv/cpu/cpu.c
@@ -49,14 +49,24 @@ static inline bool supports_extension(char ext)
}
if (!cpu_get_desc(dev, desc, sizeof(desc))) {
/*
- * skip the first 4 characters (rv32|rv64) and
- * check until underscore
+ * skip the first 4 characters (rv32|rv64)
*/
for (i = 4; i < sizeof(desc); i++) {
- if (desc[i] == '_' || desc[i] == '\0')
- break;
- if (desc[i] == ext)
- return true;
+ switch (desc[i]) {
+ case 's':
+ case 'x':
+ case 'z':
+ case '_':
+ case '\0':
+ /*
+ * Any of these characters mean the single
+ * letter extensions have all been consumed.
+ */
+ return false;
+ default:
+ if (desc[i] == ext)
+ return true;
+ }
}
}
--
2.43.0
