Messages in this thread | | | From | Andreas Schwab <> | Subject | Re: [PATCH v7 1/3] riscv: Avoid unaligned access when relocating modules | Date | Tue, 31 Oct 2023 17:35:57 +0100 |
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On Okt 31 2023, Emil Renner Berthing wrote:
>> +static int riscv_insn_rmw(void *location, u32 keep, u32 set) >> +{ >> + u16 *parcel = location; >> + u32 insn = (u32)le16_to_cpu(parcel[0]) | (u32)le16_to_cpu(parcel[1]) << 16; >> + >> + insn &= keep; >> + insn |= set; >> + >> + parcel[0] = cpu_to_le32(insn); > > Why cpu_to_le32(insn)? Unless I've misunderstood something downcasting unsigned > to unsigned values in C (eg. from u32 to u16) is defined to always discard the > most signifcant bits, so cpu_to_le16(insn) should be fine.
cpu_to_le32(insn) can't be right here anyway, since it also swaps the two u16 halves and would be the same as cpu_to_le16(insn >> 16) on big endian.
-- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
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