From 4c0742f65b4ee466546fd24b71b56516cacd4613 Mon Sep 17 00:00:00 2001 From: Vladimir Murzin Date: Thu, 10 Oct 2019 10:12:20 +0100 Subject: [PATCH] ARM: 8914/1: NOMMU: Fix exc_ret for XIP It was reported that 72cd4064fcca "NOMMU: Toggle only bits in EXC_RETURN we are really care of" breaks NOMMU+XIP combination. It happens because saved EXC_RETURN gets overwritten when data section is relocated. The fix is to propagate EXC_RETURN via register and let relocation code to commit that value into memory. Fixes: 72cd4064fcca ("ARM: 8830/1: NOMMU: Toggle only bits in EXC_RETURN we are really care of") Reported-by: afzal mohammed Tested-by: afzal mohammed Signed-off-by: Vladimir Murzin Signed-off-by: Russell King --- arch/arm/kernel/head-common.S | 5 +++-- arch/arm/kernel/head-nommu.S | 2 ++ arch/arm/mm/proc-v7m.S | 5 ++--- 3 files changed, 7 insertions(+), 5 deletions(-) diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S index a7810be..4a39828 100644 --- a/arch/arm/kernel/head-common.S +++ b/arch/arm/kernel/head-common.S @@ -68,7 +68,7 @@ ENDPROC(__vet_atags) * The following fragment of code is executed with the MMU on in MMU mode, * and uses absolute addresses; this is not position independent. * - * r0 = cp#15 control register + * r0 = cp#15 control register (exc_ret for M-class) * r1 = machine ID * r2 = atags/dtb pointer * r9 = processor ID @@ -137,7 +137,8 @@ __mmap_switched_data: #ifdef CONFIG_CPU_CP15 .long cr_alignment @ r3 #else - .long 0 @ r3 +M_CLASS(.long exc_ret) @ r3 +AR_CLASS(.long 0) @ r3 #endif .size __mmap_switched_data, . - __mmap_switched_data diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S index afa350f..0fc814b 100644 --- a/arch/arm/kernel/head-nommu.S +++ b/arch/arm/kernel/head-nommu.S @@ -201,6 +201,8 @@ M_CLASS(streq r3, [r12, #PMSAv8_MAIR1]) bic r0, r0, #V7M_SCB_CCR_IC #endif str r0, [r12, V7M_SCB_CCR] + /* Pass exc_ret to __mmap_switched */ + mov r0, r10 #endif /* CONFIG_CPU_CP15 elif CONFIG_CPU_V7M */ ret lr ENDPROC(__after_proc_init) diff --git a/arch/arm/mm/proc-v7m.S b/arch/arm/mm/proc-v7m.S index 1448f14..efebf41 100644 --- a/arch/arm/mm/proc-v7m.S +++ b/arch/arm/mm/proc-v7m.S @@ -136,9 +136,8 @@ __v7m_setup_cont: cpsie i svc #0 1: cpsid i - ldr r0, =exc_ret - orr lr, lr, #EXC_RET_THREADMODE_PROCESSSTACK - str lr, [r0] + /* Calculate exc_ret */ + orr r10, lr, #EXC_RET_THREADMODE_PROCESSSTACK ldmia sp, {r0-r3, r12} str r5, [r12, #11 * 4] @ restore the original SVC vector entry mov lr, r6 @ restore LR -- 2.7.4