From 238962ac71910d6c20162ea5230685fead1836a4 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Tue, 4 Nov 2014 11:40:46 +0100 Subject: ARM: 8191/1: decompressor: ensure I-side picks up relocated code To speed up decompression, the decompressor sets up a flat, cacheable mapping of memory. However, when there is insufficient space to hold the page tables for this mapping, we don't bother to enable the caches and subsequently skip all the cache maintenance hooks. Skipping the cache maintenance before jumping to the relocated code allows the processor to predict the branch and populate the I-cache with stale data before the relocation loop has completed (since a bootloader may have SCTLR.I set, which permits normal, cacheable instruction fetches regardless of SCTLR.M). This patch moves the cache maintenance check into the maintenance routines themselves, allowing the v6/v7 versions to invalidate the I-cache regardless of the MMU state. Cc: Reported-by: Marc Carino Tested-by: Julien Grall Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/boot/compressed/head.S | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) (limited to 'arch') diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index 413fd94b5301..68be9017593d 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -397,8 +397,7 @@ dtb_check_done: add sp, sp, r6 #endif - tst r4, #1 - bleq cache_clean_flush + bl cache_clean_flush adr r0, BSYM(restart) add r0, r0, r6 @@ -1047,6 +1046,8 @@ cache_clean_flush: b call_cache_fn __armv4_mpu_cache_flush: + tst r4, #1 + movne pc, lr mov r2, #1 mov r3, #0 mcr p15, 0, ip, c7, c6, 0 @ invalidate D cache @@ -1064,6 +1065,8 @@ __armv4_mpu_cache_flush: mov pc, lr __fa526_cache_flush: + tst r4, #1 + movne pc, lr mov r1, #0 mcr p15, 0, r1, c7, c14, 0 @ clean and invalidate D cache mcr p15, 0, r1, c7, c5, 0 @ flush I cache @@ -1072,13 +1075,16 @@ __fa526_cache_flush: __armv6_mmu_cache_flush: mov r1, #0 - mcr p15, 0, r1, c7, c14, 0 @ clean+invalidate D + tst r4, #1 + mcreq p15, 0, r1, c7, c14, 0 @ clean+invalidate D mcr p15, 0, r1, c7, c5, 0 @ invalidate I+BTB - mcr p15, 0, r1, c7, c15, 0 @ clean+invalidate unified + mcreq p15, 0, r1, c7, c15, 0 @ clean+invalidate unified mcr p15, 0, r1, c7, c10, 4 @ drain WB mov pc, lr __armv7_mmu_cache_flush: + tst r4, #1 + bne iflush mrc p15, 0, r10, c0, c1, 5 @ read ID_MMFR1 tst r10, #0xf << 16 @ hierarchical cache (ARMv7) mov r10, #0 @@ -1139,6 +1145,8 @@ iflush: mov pc, lr __armv5tej_mmu_cache_flush: + tst r4, #1 + movne pc, lr 1: mrc p15, 0, r15, c7, c14, 3 @ test,clean,invalidate D cache bne 1b mcr p15, 0, r0, c7, c5, 0 @ flush I cache @@ -1146,6 +1154,8 @@ __armv5tej_mmu_cache_flush: mov pc, lr __armv4_mmu_cache_flush: + tst r4, #1 + movne pc, lr mov r2, #64*1024 @ default: 32K dcache size (*2) mov r11, #32 @ default: 32 byte line size mrc p15, 0, r3, c0, c0, 1 @ read cache type @@ -1179,6 +1189,8 @@ no_cache_id: __armv3_mmu_cache_flush: __armv3_mpu_cache_flush: + tst r4, #1 + movne pc, lr mov r1, #0 mcr p15, 0, r1, c7, c0, 0 @ invalidate whole cache v3 mov pc, lr -- cgit v1.2.3 From 08b964ff3c51b10aaf2e6ba639f40054c09f0f7a Mon Sep 17 00:00:00 2001 From: Nathan Lynch Date: Mon, 10 Nov 2014 23:46:27 +0100 Subject: ARM: 8198/1: make kuser helpers depend on MMU MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The kuser helpers page is not set up on non-MMU systems, so it does not make sense to allow CONFIG_KUSER_HELPERS to be enabled when CONFIG_MMU=n. Allowing it to be set on !MMU results in an oops in set_tls (used in execve and the arm_syscall trap handler): Unhandled exception: IPSR = 00000005 LR = fffffff1 CPU: 0 PID: 1 Comm: swapper Not tainted 3.18.0-rc1-00041-ga30465a #216 task: 8b838000 ti: 8b82a000 task.ti: 8b82a000 PC is at flush_thread+0x32/0x40 LR is at flush_thread+0x21/0x40 pc : [<8f00157a>] lr : [<8f001569>] psr: 4100000b sp : 8b82be20 ip : 00000000 fp : 8b83c000 r10: 00000001 r9 : 88018c84 r8 : 8bb85000 r7 : 8b838000 r6 : 00000000 r5 : 8bb77400 r4 : 8b82a000 r3 : ffff0ff0 r2 : 8b82a000 r1 : 00000000 r0 : 88020354 xPSR: 4100000b CPU: 0 PID: 1 Comm: swapper Not tainted 3.18.0-rc1-00041-ga30465a #216 [<8f002bc1>] (unwind_backtrace) from [<8f002033>] (show_stack+0xb/0xc) [<8f002033>] (show_stack) from [<8f00265b>] (__invalid_entry+0x4b/0x4c) As best I can tell this issue existed for the set_tls ARM syscall before commit fbfb872f5f41 "ARM: 8148/1: flush TLS and thumbee register state during exec" consolidated the TLS manipulation code into the set_tls helper function, but now that we're using it to flush register state during execve, !MMU users encounter the oops at the first exec. Prevent CONFIG_MMU=n configurations from enabling CONFIG_KUSER_HELPERS. Fixes: fbfb872f5f41 (ARM: 8148/1: flush TLS and thumbee register state during exec) Signed-off-by: Nathan Lynch Reported-by: Stefan Agner Acked-by: Uwe Kleine-König Cc: stable@vger.kernel.org Signed-off-by: Russell King --- arch/arm/mm/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'arch') diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index ae69809a9e47..7eb94e6fc376 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -798,6 +798,7 @@ config NEED_KUSER_HELPERS config KUSER_HELPERS bool "Enable kuser helpers in vector page" if !NEED_KUSER_HELPERS + depends on MMU default y help Warning: disabling this option may break user programs. -- cgit v1.2.3