From 24c66dfd569c4744fc43aea638155ad2dc1499d8 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 15 Nov 2016 13:55:59 +0000 Subject: [PATCH 1/4] ARM: fix backtrace Recent kernels have changed their behaviour to be more inconsistent when handling printk continuations. With todays kernels, the output looks sane on the console, but dmesg splits individual printk()s which do not have the KERN_CONT prefix into separate lines. Since the assembly code is not trivial to add the KERN_CONT, and we ideally want to avoid using KERN_CONT (as multiple printk()s can race between different threads), convert the assembly dumping the register values to C code, and have the C code build the output a line at a time before dumping to the console. This avoids the KERN_CONT issue, and also avoids situations where the output is intermixed with other console activity. Signed-off-by: Russell King --- arch/arm/kernel/traps.c | 20 ++++++++++++++++++++ arch/arm/lib/backtrace.S | 37 +++---------------------------------- 2 files changed, 23 insertions(+), 34 deletions(-) diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index bc698383e822..9688ec0c6ef4 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -74,6 +74,26 @@ void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs)); } +void dump_backtrace_stm(u32 *stack, u32 instruction) +{ + char str[80], *p; + unsigned int x; + int reg; + + for (reg = 10, x = 0, p = str; reg >= 0; reg--) { + if (instruction & BIT(reg)) { + p += sprintf(p, " r%d:%08x", reg, *stack--); + if (++x == 6) { + x = 0; + p = str; + printk("%s\n", str); + } + } + } + if (p != str) + printk("%s\n", str); +} + #ifndef CONFIG_ARM_UNWIND /* * Stack pointers should always be within the kernels view of diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S index fab5a50503ae..7d7952e5a3b1 100644 --- a/arch/arm/lib/backtrace.S +++ b/arch/arm/lib/backtrace.S @@ -10,6 +10,7 @@ * 27/03/03 Ian Molton Clean up CONFIG_CPU * */ +#include #include #include .text @@ -83,13 +84,13 @@ for_each_frame: tst frame, mask @ Check for address exceptions teq r3, r1, lsr #11 ldreq r0, [frame, #-8] @ get sp subeq r0, r0, #4 @ point at the last arg - bleq .Ldumpstm @ dump saved registers + bleq dump_backtrace_stm @ dump saved registers 1004: ldr r1, [sv_pc, #0] @ if stmfd sp!, {..., fp, ip, lr, pc} ldr r3, .Ldsi @ instruction exists, teq r3, r1, lsr #11 subeq r0, frame, #16 - bleq .Ldumpstm @ dump saved registers + bleq dump_backtrace_stm @ dump saved registers teq sv_fp, #0 @ zero saved fp means beq no_frame @ no further frames @@ -112,38 +113,6 @@ ENDPROC(c_backtrace) .long 1004b, 1006b .popsection -#define instr r4 -#define reg r5 -#define stack r6 - -.Ldumpstm: stmfd sp!, {instr, reg, stack, r7, lr} - mov stack, r0 - mov instr, r1 - mov reg, #10 - mov r7, #0 -1: mov r3, #1 - ARM( tst instr, r3, lsl reg ) - THUMB( lsl r3, reg ) - THUMB( tst instr, r3 ) - beq 2f - add r7, r7, #1 - teq r7, #6 - moveq r7, #0 - adr r3, .Lcr - addne r3, r3, #1 @ skip newline - ldr r2, [stack], #-4 - mov r1, reg - adr r0, .Lfp - bl printk -2: subs reg, reg, #1 - bpl 1b - teq r7, #0 - adrne r0, .Lcr - blne printk - ldmfd sp!, {instr, reg, stack, r7, pc} - -.Lfp: .asciz " r%d:%08x%s" -.Lcr: .asciz "\n" .Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n" .align .Ldsi: .word 0xe92dd800 >> 11 @ stmfd sp!, {... fp, ip, lr, pc} From 544457fa278216c5fcea6a16e9b2ee8aadaca0ca Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Tue, 1 Nov 2016 21:58:36 +0100 Subject: [PATCH 2/4] ARM: 8624/1: proc-v7m.S: fix init section name There is no .text.init sections. Signed-off-by: Nicolas Pitre Signed-off-by: Russell King --- arch/arm/mm/proc-v7m.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/mm/proc-v7m.S b/arch/arm/mm/proc-v7m.S index f6d333f09bfe..8dea61640cc1 100644 --- a/arch/arm/mm/proc-v7m.S +++ b/arch/arm/mm/proc-v7m.S @@ -96,7 +96,7 @@ ENTRY(cpu_cm7_proc_fin) ret lr ENDPROC(cpu_cm7_proc_fin) - .section ".text.init", #alloc, #execinstr + .section ".init.text", #alloc, #execinstr __v7m_cm7_setup: mov r8, #(V7M_SCB_CCR_DC | V7M_SCB_CCR_IC| V7M_SCB_CCR_BP) From 256ff1cf6b44cba9c9c2059f4516259e9319a808 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Tue, 15 Nov 2016 14:00:53 +0100 Subject: [PATCH 3/4] ARM: 8628/1: dma-mapping: preallocate DMA-debug hash tables in core_initcall fs_initcall is definitely too late to initialize DMA-debug hash tables, because some drivers might get probed and use DMA mapping framework already in core_initcall. Late initialization of DMA-debug results in false warning about accessing memory, that was not allocated, like this one: ------------[ cut here ]------------ WARNING: CPU: 5 PID: 1 at lib/dma-debug.c:1104 check_unmap+0xa1c/0xe50 exynos-sysmmu 10a60000.sysmmu: DMA-API: device driver tries to free DMA memory it has not allocated [device address=0x000000006ebd0000] [size=16384 bytes] Modules linked in: CPU: 5 PID: 1 Comm: swapper/0 Not tainted 4.9.0-rc5-00028-g39dde3d-dirty #44 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [] (unwind_backtrace) from [] (show_stack+0x20/0x24) [] (show_stack) from [] (dump_stack+0x84/0xa0) [] (dump_stack) from [] (__warn+0x14c/0x180) [] (__warn) from [] (warn_slowpath_fmt+0x48/0x50) [] (warn_slowpath_fmt) from [] (check_unmap+0xa1c/0xe50) [] (check_unmap) from [] (debug_dma_unmap_page+0x98/0xc8) [] (debug_dma_unmap_page) from [] (exynos_iommu_domain_free+0x158/0x380) [] (exynos_iommu_domain_free) from [] (iommu_domain_free+0x34/0x60) [] (iommu_domain_free) from [] (release_iommu_mapping+0x30/0xb8) [] (release_iommu_mapping) from [] (arm_iommu_release_mapping+0x4c/0x50) [] (arm_iommu_release_mapping) from [] (s5p_mfc_probe+0x640/0x80c) [] (s5p_mfc_probe) from [] (platform_drv_probe+0x70/0x148) [] (platform_drv_probe) from [] (driver_probe_device+0x12c/0x6b0) [] (driver_probe_device) from [] (__driver_attach+0x128/0x17c) [] (__driver_attach) from [] (bus_for_each_dev+0x88/0xc8) [] (bus_for_each_dev) from [] (driver_attach+0x34/0x58) [] (driver_attach) from [] (bus_add_driver+0x18c/0x32c) [] (bus_add_driver) from [] (driver_register+0x98/0x148) [] (driver_register) from [] (__platform_driver_register+0x58/0x74) [] (__platform_driver_register) from [] (s5p_mfc_driver_init+0x1c/0x20) [] (s5p_mfc_driver_init) from [] (do_one_initcall+0x64/0x258) [] (do_one_initcall) from [] (kernel_init_freeable+0x3d0/0x4d0) [] (kernel_init_freeable) from [] (kernel_init+0x18/0x134) [] (kernel_init) from [] (ret_from_fork+0x14/0x3c) ---[ end trace dc54c54bd3581296 ]--- This patch moves initialization of DMA-debug to core_initcall. This is safe from the initialization perspective. dma_debug_do_init() internally calls debugfs functions and debugfs also gets initialised at core_initcall(), and that is earlier than arch code in the link order, so it will get initialized just before the DMA-debug. Reported-by: Seung-Woo Kim Signed-off-by: Marek Szyprowski Signed-off-by: Russell King --- arch/arm/mm/dma-mapping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index ab4f74536057..ab7710002ba6 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1167,7 +1167,7 @@ static int __init dma_debug_do_init(void) dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); return 0; } -fs_initcall(dma_debug_do_init); +core_initcall(dma_debug_do_init); #ifdef CONFIG_ARM_DMA_USE_IOMMU From 2a3811068fbc6bf09bb09d166b65394b091c1085 Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 16 Nov 2016 23:51:19 +0000 Subject: [PATCH 4/4] ARM: Fix XIP kernels Commit 7619751f8c90 ("ARM: 8595/2: apply more __ro_after_init") caused a regression with XIP kernels by moving the __ro_after_init data into the read-only section. With XIP kernels, the read-only section is located in read-only memory from the very beginning. Work around this by moving the __ro_after_init data back into the .data section, which will be in RAM, and hence will be writable. It should be noted that in doing so, this remains writable after init. Fixes: 7619751f8c90 ("ARM: 8595/2: apply more __ro_after_init") Reported-by: Andrea Merello Tested-by: Andrea Merello [ XIP stm32 ] Tested-by: Alexandre Torgue Signed-off-by: Russell King --- arch/arm/kernel/vmlinux-xip.lds.S | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S index 7fa487ef7e2f..37b2a11af345 100644 --- a/arch/arm/kernel/vmlinux-xip.lds.S +++ b/arch/arm/kernel/vmlinux-xip.lds.S @@ -3,6 +3,9 @@ * Written by Martin Mares */ +/* No __ro_after_init data in the .rodata section - which will always be ro */ +#define RO_AFTER_INIT_DATA + #include #include #include @@ -223,6 +226,8 @@ SECTIONS . = ALIGN(PAGE_SIZE); __init_end = .; + *(.data..ro_after_init) + NOSAVE_DATA CACHELINE_ALIGNED_DATA(L1_CACHE_BYTES) READ_MOSTLY_DATA(L1_CACHE_BYTES)