[PATCH v1 02/13] arm64: Do not enable uaccess for invalidate_icache_range

[Fuad Tabba]

invalidate_icache_range() works on the kernel linear map, and
doesn't need uaccess. Remove the code that toggles
uaccess_ttbr0_enable, as well as the code that emits an entry
into the exception table (via the macro
invalidate_icache_by_line).

No functional change intended.

Reported-by: Catalin Marinas <catalin.marinas at arm.com>
Reported-by: Will Deacon <will at kernel.org>
Link: https://lore.kernel.org/linux-arch/20200511110014.lb9PEahJ4hVOYrbwIb_qUHXyNy9KQzNFdb_I3YlzY6A@z/
Signed-off-by: Fuad Tabba <tabba at google.com>
---
 arch/arm64/include/asm/cacheflush.h |  2 +-
 arch/arm64/mm/cache.S               | 11 +----------
 2 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index 52e5c1623224..a586afa84172 100644
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h
@@ -57,7 +57,7 @@
  *		- size   - region size
  */
 extern void __flush_icache_range(unsigned long start, unsigned long end);
-extern int  invalidate_icache_range(unsigned long start, unsigned long end);
+extern void invalidate_icache_range(unsigned long start, unsigned long end);
 extern void __flush_dcache_area(void *addr, size_t len);
 extern void __inval_dcache_area(void *addr, size_t len);
 extern void __clean_dcache_area_poc(void *addr, size_t len);
diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index 092f73acdf9a..6babaaf34f17 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -105,21 +105,12 @@ SYM_FUNC_END(__flush_cache_user_range)
  */
 SYM_FUNC_START(invalidate_icache_range)
 alternative_if ARM64_HAS_CACHE_DIC
-	mov	x0, xzr
 	isb
 	ret
 alternative_else_nop_endif
 
-	uaccess_ttbr0_enable x2, x3, x4
-
-	invalidate_icache_by_line x0, x1, x2, x3, 1, 2f
-	mov	x0, xzr
-1:
-	uaccess_ttbr0_disable x1, x2
+	invalidate_icache_by_line x0, x1, x2, x3, 0, 0f
 	ret
-2:
-	mov	x0, #-EFAULT
-	b	1b
 SYM_FUNC_END(invalidate_icache_range)
 
 /*
-- 
2.31.1.607.g51e8a6a459-goog