Messages in this thread | | | Subject | Re: [PATCH] arm64/cache: fix -Woverride-init compiler warnings | From | Qian Cai <> | Date | Mon, 5 Aug 2019 07:47:37 -0400 |
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> On Aug 5, 2019, at 5:52 AM, Will Deacon <will@kernel.org> wrote: > > On Fri, Aug 02, 2019 at 11:32:24AM -0400, Qian Cai wrote: >> The commit 155433cb365e ("arm64: cache: Remove support for ASID-tagged >> VIVT I-caches") introduced some compiation warnings from GCC, >> >> arch/arm64/kernel/cpuinfo.c:38:26: warning: initialized field >> overwritten [-Woverride-init] >> [ICACHE_POLICY_VIPT] = "VIPT", >> ^~~~~~ >> arch/arm64/kernel/cpuinfo.c:38:26: note: (near initialization for >> 'icache_policy_str[2]') >> arch/arm64/kernel/cpuinfo.c:39:26: warning: initialized field >> overwritten [-Woverride-init] >> [ICACHE_POLICY_PIPT] = "PIPT", >> ^~~~~~ >> arch/arm64/kernel/cpuinfo.c:39:26: note: (near initialization for >> 'icache_policy_str[3]') >> arch/arm64/kernel/cpuinfo.c:40:27: warning: initialized field >> overwritten [-Woverride-init] >> [ICACHE_POLICY_VPIPT] = "VPIPT", >> ^~~~~~~ >> arch/arm64/kernel/cpuinfo.c:40:27: note: (near initialization for >> 'icache_policy_str[0]') >> >> because it initializes icache_policy_str[0 ... 3] twice. >> >> Fixes: 155433cb365e ("arm64: cache: Remove support for ASID-tagged VIVT I-caches") >> Signed-off-by: Qian Cai <cai@lca.pw> >> --- >> arch/arm64/kernel/cpuinfo.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c >> index 876055e37352..193b38da8d96 100644 >> --- a/arch/arm64/kernel/cpuinfo.c >> +++ b/arch/arm64/kernel/cpuinfo.c >> @@ -34,10 +34,10 @@ >> static struct cpuinfo_arm64 boot_cpu_data; >> >> static char *icache_policy_str[] = { >> - [0 ... ICACHE_POLICY_PIPT] = "RESERVED/UNKNOWN", >> + [ICACHE_POLICY_VPIPT] = "VPIPT", >> + [ICACHE_POLICY_VPIPT + 1] = "RESERVED/UNKNOWN", >> [ICACHE_POLICY_VIPT] = "VIPT", >> [ICACHE_POLICY_PIPT] = "PIPT", >> - [ICACHE_POLICY_VPIPT] = "VPIPT", > > I really don't like this patch. Using "[0 ... MAXIDX] = <default>" is a > useful idiom and I think the code is more error-prone the way you have > restructured it. > > Why are you passing -Woverride-init to the compiler anyway? There's only > one Makefile that references that option, and it's specific to a pinctrl > driver.
Those extra warnings can be enabled by “make W=1”. “-Woverride-init “ seems to be useful to catch potential developer mistakes with unintented double-initializations. It is normal to start to fix the most of false-positives first before globally enabling the flag by default just like “-Wimplicit-fallthrough” mentioned in,
https://lwn.net/Articles/794944/
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