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Re: [PATCH 1/4] util/cacheflush: fix illegal instruction on windows-arm6
From: |
Peter Maydell |
Subject: |
Re: [PATCH 1/4] util/cacheflush: fix illegal instruction on windows-arm64 |
Date: |
Tue, 14 Feb 2023 16:44:31 +0000 |
On Mon, 13 Feb 2023 at 20:50, Pierrick Bouvier
<pierrick.bouvier@linaro.org> wrote:
>
> mrs instruction fails as an illegal instruction.
> For now, no cache information is retrieved for this platform.
> It could be specialized later, using Windows API.
Unless I'm misreading the code, there's a sys_cache_info()
implementation that's only guarded by if defined(_WIN32), so
presumably we're using that on AArch64 also. Does it return
sensible values ?
> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
> ---
> util/cacheflush.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/util/cacheflush.c b/util/cacheflush.c
> index 2c2c73e085..149f103d32 100644
> --- a/util/cacheflush.c
> +++ b/util/cacheflush.c
> @@ -121,8 +121,9 @@ static void sys_cache_info(int *isize, int *dsize)
> static bool have_coherent_icache;
> #endif
>
> -#if defined(__aarch64__) && !defined(CONFIG_DARWIN)
> +#if defined(__aarch64__) && !defined(CONFIG_DARWIN) && !defined(CONFIG_WIN32)
> /* Apple does not expose CTR_EL0, so we must use system interfaces. */
> +/* Does not work on windows-arm64, illegal instruction using mrs */
This comment should be better integrated with the previous, because
the reason for the illegal instruction exception on Windows is the
same as for macos -- the OS doesn't expose CTR_EL0 to userspace.
> static uint64_t save_ctr_el0;
> static void arch_cache_info(int *isize, int *dsize)
> {
> @@ -225,7 +226,7 @@ static void __attribute__((constructor))
> init_cache_info(void)
>
> /* Caches are coherent and do not require flushing; symbol inline. */
>
> -#elif defined(__aarch64__)
> +#elif defined(__aarch64__) && !defined(CONFIG_WIN32)
This will cause us to not use the generic aarch64 flush_idcache_range(),
which uses DC CVAU and IC IVAU. Does that not work on Windows?
If it doesn't then I think the ifdeffery would be more clearly
structured as
#elif defined(__aarch64__)
ifdef CONFIG_DARWIN
[macos implementation of flush_idcache_range]
#elif defined(CONFIG_WIN32)
/* Explanation here of why the generic version doesn't work */
#else
/* generic version */
#endif
#elif defined(__mips__)
etc
thanks
-- PMM
[PATCH 2/4] sysemu/os-win32: fix setjmp/longjmp on windows-arm64, Pierrick Bouvier, 2023/02/13
[PATCH 4/4] target/ppc: fix warning with clang-15, Pierrick Bouvier, 2023/02/13