Thread (13 messages) flat view 13 messages, 3 authors, 2021-03-24

Re: [PATCH 2/5] arm64: vdso: Remove redundant calls to flush_dcache_page()

From: Vincenzo Frascino <vincenzo.frascino@arm.com>
Date: 2021-03-18 18:06:40

On 3/18/21 5:07 PM, Will Deacon wrote:
flush_dcache_page() ensures that the 'PG_dcache_clean' flag for its
'page' argument is clear so that cache maintenance will be performed
if the page is mapped into userspace with execute permissions.

Newly allocated pages have this flag clear, so there is no need to call
flush_dcache_page() for the compat vdso or signal pages. Remove the
redundant calls.

Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
quoted hunk ↗ jump to hunk
---
 arch/arm64/kernel/vdso.c | 2 --
 1 file changed, 2 deletions(-)
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
index 2d057a4dc787..421411981dc3 100644
--- a/arch/arm64/kernel/vdso.c
+++ b/arch/arm64/kernel/vdso.c
@@ -306,7 +306,6 @@ static int aarch32_alloc_kuser_vdso_page(void)
 	memcpy((void *)(vdso_page + 0x1000 - kuser_sz), __kuser_helper_start,
 	       kuser_sz);
 	aarch32_vectors_page = virt_to_page(vdso_page);
-	flush_dcache_page(aarch32_vectors_page);
 	return 0;
 }
 
@@ -322,7 +321,6 @@ static int aarch32_alloc_sigpage(void)
 
 	memcpy((void *)sigpage, __aarch32_sigret_code_start, sigret_sz);
 	aarch32_sig_page = virt_to_page(sigpage);
-	flush_dcache_page(aarch32_sig_page);
 	return 0;
 }
 
-- 
Regards,
Vincenzo

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