linux-kernel - Re: [PATCH v2 1/8] riscv: remove unused functions in traps

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Message-ID: <114052a2-6e2f-46cb-acb0-8d85c3b584bb@rivosinc.com>
Date:   Mon, 9 Oct 2023 15:02:43 +0200
From:   Clément Léger <cleger@...osinc.com>
To:     Björn Töpel <bjorn@...nel.org>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>
Cc:     Atish Patra <atishp@...osinc.com>,
        Andrew Jones <ajones@...tanamicro.com>,
        Evan Green <evan@...osinc.com>,
        Björn Topel <bjorn@...osinc.com>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Ron Minnich <rminnich@...il.com>,
        Daniel Maslowski <cyrevolt@...glemail.com>,
        Conor Dooley <conor@...nel.org>
Subject: Re: [PATCH v2 1/8] riscv: remove unused functions in
 traps_misaligned.c



On 04/10/2023 18:51, Björn Töpel wrote:
> Clément Léger <cleger@...osinc.com> writes:
> 
>> Replace macros by the only two function calls that are done from this
>> file, store_u8() and load_u8().
>>
>> Signed-off-by: Clément Léger <cleger@...osinc.com>
>> ---
>>  arch/riscv/kernel/traps_misaligned.c | 46 +++++-----------------------
>>  1 file changed, 7 insertions(+), 39 deletions(-)
>>
>> diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c
>> index 378f5b151443..e7bfb33089c1 100644
>> --- a/arch/riscv/kernel/traps_misaligned.c
>> +++ b/arch/riscv/kernel/traps_misaligned.c
>> @@ -151,51 +151,19 @@
>>  #define PRECISION_S 0
>>  #define PRECISION_D 1
>>  
>> -#define DECLARE_UNPRIVILEGED_LOAD_FUNCTION(type, insn)			\
>> -static inline type load_##type(const type *addr)			\
>> -{									\
>> -	type val;							\
>> -	asm (#insn " %0, %1"						\
>> -	: "=&r" (val) : "m" (*addr));					\
>> -	return val;							\
>> -}
>> +static inline u8 load_u8(const u8 *addr)
> 
> Really a nit, and applies to the whole file: "static inline" in a .c
> file is just useless.

Oh yes clearly, I should have fixed that while factorizing, I simply
kept them from the previous code.

> 
>> +{
>> +	u8 val;
>>  
>> -#define DECLARE_UNPRIVILEGED_STORE_FUNCTION(type, insn)			\
>> -static inline void store_##type(type *addr, type val)			\
>> -{									\
>> -	asm volatile (#insn " %0, %1\n"					\
>> -	: : "r" (val), "m" (*addr));					\
>> -}
>> +	asm volatile("lbu %0, %1" : "=&r" (val) : "m" (*addr));
> 
> Why do you need early clobber here?

Ditto, copy pasted from existing code but I don't think there is a need
for early clobber here.

Clément

> 
> 
> Björn