ARM: 9393/1: mm: Use conditionals for CFI branches

Commit 9385/2 introduced a few branches inside function prototypes when using CFI in order to deal with the situation where CFI inserts a few bytes of function information in front of the symbol. This is not good for older CPUs where every cycle counts. Commit 9386/2 alleviated the situation a bit by using aliases for the cache functions with identical signatures. This leaves the coherent cache flush functions *_coherent_kern_range() with these branches to the corresponing *_coherent_user_range() around, since their return type differ and they therefore cannot be aliased. Solve this by a simple ifdef so at least we can use fallthroughs when compiling without CFI enabled. Link: https://lore.kernel.org/linux-arm-kernel/Zi+e9M%2Ff5b%2FSto9H@shell.armlinux.org.uk/ Suggested-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2024-05-02 08:13:24 +01:00 · 2024-05-02 08:13:24 +01:00 · 7b749aad1f
commit 7b749aad1f
parent 1a4fec49ef
20 changed files with 42 additions and 0 deletions
--- a/arch/arm/mm/cache-fa.S
+++ b/arch/arm/mm/cache-fa.S
@ -112,7 +112,9 @@ SYM_FUNC_END(fa_flush_user_cache_range)
 *	- end	 - virtual end address
 */
 SYM_TYPED_FUNC_START(fa_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	fa_coherent_user_range
+#endif
 SYM_FUNC_END(fa_coherent_kern_range)

 /*
--- a/arch/arm/mm/cache-v4.S
+++ b/arch/arm/mm/cache-v4.S
@ -104,7 +104,9 @@ SYM_FUNC_END(v4_coherent_user_range)
 *	- size	- region size
 */
 SYM_TYPED_FUNC_START(v4_flush_kern_dcache_area)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	v4_dma_flush_range
+#endif
 SYM_FUNC_END(v4_flush_kern_dcache_area)

 /*
--- a/arch/arm/mm/cache-v4wb.S
+++ b/arch/arm/mm/cache-v4wb.S
@ -136,7 +136,9 @@ SYM_FUNC_END(v4wb_flush_user_cache_range)
 */
 SYM_TYPED_FUNC_START(v4wb_flush_kern_dcache_area)
 	add	r1, r0, r1
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	v4wb_coherent_user_range
+#endif
 SYM_FUNC_END(v4wb_flush_kern_dcache_area)

 /*
@ -150,7 +152,9 @@ SYM_FUNC_END(v4wb_flush_kern_dcache_area)
 *	- end	 - virtual end address
 */
 SYM_TYPED_FUNC_START(v4wb_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	v4wb_coherent_user_range
+#endif
 SYM_FUNC_END(v4wb_coherent_kern_range)

 /*
--- a/arch/arm/mm/cache-v4wt.S
+++ b/arch/arm/mm/cache-v4wt.S
@ -108,7 +108,9 @@ SYM_FUNC_END(v4wt_flush_user_cache_range)
 *	- end	 - virtual end address
 */
 SYM_TYPED_FUNC_START(v4wt_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	v4wt_coherent_user_range
+#endif
 SYM_FUNC_END(v4wt_coherent_kern_range)

 /*
--- a/arch/arm/mm/cache-v6.S
+++ b/arch/arm/mm/cache-v6.S
@ -117,7 +117,9 @@ SYM_FUNC_END(v6_flush_user_cache_range)
 *	- the Icache does not read data from the write buffer
 */
 SYM_TYPED_FUNC_START(v6_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	v6_coherent_user_range
+#endif
 SYM_FUNC_END(v6_coherent_kern_range)

 /*
--- a/arch/arm/mm/cache-v7.S
+++ b/arch/arm/mm/cache-v7.S
@ -261,7 +261,9 @@ SYM_FUNC_END(v7_flush_user_cache_range)
 *	- the Icache does not read data from the write buffer
 */
 SYM_TYPED_FUNC_START(v7_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	v7_coherent_user_range
+#endif
 SYM_FUNC_END(v7_coherent_kern_range)

 /*
--- a/arch/arm/mm/cache-v7m.S
+++ b/arch/arm/mm/cache-v7m.S
@ -286,7 +286,9 @@ SYM_FUNC_END(v7m_flush_user_cache_range)
 *	- the Icache does not read data from the write buffer
 */
 SYM_TYPED_FUNC_START(v7m_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	v7m_coherent_user_range
+#endif
 SYM_FUNC_END(v7m_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-arm1020.S
+++ b/arch/arm/mm/proc-arm1020.S
@ -203,7 +203,9 @@ SYM_FUNC_END(arm1020_flush_user_cache_range)
 *	- end	- virtual end address
 */
 SYM_TYPED_FUNC_START(arm1020_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	arm1020_coherent_user_range
+#endif
 SYM_FUNC_END(arm1020_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-arm1020e.S
+++ b/arch/arm/mm/proc-arm1020e.S
@ -200,7 +200,9 @@ SYM_FUNC_END(arm1020e_flush_user_cache_range)
 *	- end	- virtual end address
 */
 SYM_TYPED_FUNC_START(arm1020e_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	arm1020e_coherent_user_range
+#endif
 SYM_FUNC_END(arm1020e_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-arm1022.S
+++ b/arch/arm/mm/proc-arm1022.S
@ -199,7 +199,9 @@ SYM_FUNC_END(arm1022_flush_user_cache_range)
 *	- end	- virtual end address
 */
 SYM_TYPED_FUNC_START(arm1022_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	arm1022_coherent_user_range
+#endif
 SYM_FUNC_END(arm1022_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-arm1026.S
+++ b/arch/arm/mm/proc-arm1026.S
@ -194,7 +194,9 @@ SYM_FUNC_END(arm1026_flush_user_cache_range)
 *	- end	- virtual end address
 */
 SYM_TYPED_FUNC_START(arm1026_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	arm1026_coherent_user_range
+#endif
 SYM_FUNC_END(arm1026_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-arm920.S
+++ b/arch/arm/mm/proc-arm920.S
@ -180,7 +180,9 @@ SYM_FUNC_END(arm920_flush_user_cache_range)
 *	- end	- virtual end address
 */
 SYM_TYPED_FUNC_START(arm920_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	arm920_coherent_user_range
+#endif
 SYM_FUNC_END(arm920_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-arm922.S
+++ b/arch/arm/mm/proc-arm922.S
@ -182,7 +182,9 @@ SYM_FUNC_END(arm922_flush_user_cache_range)
 *	- end	- virtual end address
 */
 SYM_TYPED_FUNC_START(arm922_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	arm922_coherent_user_range
+#endif
 SYM_FUNC_END(arm922_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-arm925.S
+++ b/arch/arm/mm/proc-arm925.S
@ -229,7 +229,9 @@ SYM_FUNC_END(arm925_flush_user_cache_range)
 *	- end	- virtual end address
 */
 SYM_TYPED_FUNC_START(arm925_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	arm925_coherent_user_range
+#endif
 SYM_FUNC_END(arm925_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-arm926.S
+++ b/arch/arm/mm/proc-arm926.S
@ -192,7 +192,9 @@ SYM_FUNC_END(arm926_flush_user_cache_range)
 *	- end	- virtual end address
 */
 SYM_TYPED_FUNC_START(arm926_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	arm926_coherent_user_range
+#endif
 SYM_FUNC_END(arm926_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-arm940.S
+++ b/arch/arm/mm/proc-arm940.S
@ -153,7 +153,9 @@ SYM_FUNC_END(arm940_coherent_kern_range)
 *	- end	- virtual end address
 */
 SYM_TYPED_FUNC_START(arm940_coherent_user_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	arm940_flush_kern_dcache_area
+#endif
 SYM_FUNC_END(arm940_coherent_user_range)

 /*
--- a/arch/arm/mm/proc-arm946.S
+++ b/arch/arm/mm/proc-arm946.S
@ -173,7 +173,9 @@ SYM_FUNC_END(arm946_flush_user_cache_range)
 *	- end	- virtual end address
 */
 SYM_TYPED_FUNC_START(arm946_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	arm946_coherent_user_range
+#endif
 SYM_FUNC_END(arm946_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-feroceon.S
+++ b/arch/arm/mm/proc-feroceon.S
@ -208,7 +208,9 @@ SYM_FUNC_END(feroceon_flush_user_cache_range)
 */
 	.align	5
 SYM_TYPED_FUNC_START(feroceon_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	feroceon_coherent_user_range
+#endif
 SYM_FUNC_END(feroceon_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-mohawk.S
+++ b/arch/arm/mm/proc-mohawk.S
@ -163,7 +163,9 @@ SYM_FUNC_END(mohawk_flush_user_cache_range)
 *	- end	- virtual end address
 */
 SYM_TYPED_FUNC_START(mohawk_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	mohawk_coherent_user_range
+#endif
 SYM_FUNC_END(mohawk_coherent_kern_range)

 /*
--- a/arch/arm/mm/proc-xsc3.S
+++ b/arch/arm/mm/proc-xsc3.S
@ -223,7 +223,9 @@ SYM_FUNC_END(xsc3_flush_user_cache_range)
 *	it also trashes the mini I-cache used by JTAG debuggers.
 */
 SYM_TYPED_FUNC_START(xsc3_coherent_kern_range)
+#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
 	b	xsc3_coherent_user_range
+#endif
 SYM_FUNC_END(xsc3_coherent_kern_range)

 SYM_TYPED_FUNC_START(xsc3_coherent_user_range)