From d624833f5984d484c5e3196f34b926f9e71dafee Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 17 Feb 2021 20:26:23 +0100 Subject: [PATCH 1/4] ARM: 9063/1: mm: reduce maximum number of CPUs if DEBUG_KMAP_LOCAL is enabled The debugging code for kmap_local() doubles the number of per-CPU fixmap slots allocated for kmap_local(), in order to use half of them as guard regions. This causes the fixmap region to grow downwards beyond the start of its reserved window if the supported number of CPUs is large, and collide with the newly added virtual DT mapping right below it, which is obviously not good. One manifestation of this is EFI boot on a kernel built with NR_CPUS=32 and CONFIG_DEBUG_KMAP_LOCAL=y, which may pass the FDT in highmem, resulting in block entries below the fixmap region that the fixmap code misidentifies as fixmap table entries, and subsequently tries to dereference using a phys-to-virt translation that is only valid for lowmem. This results in a cryptic splat such as the one below. ftrace: allocating 45548 entries in 89 pages 8<--- cut here --- Unable to handle kernel paging request at virtual address fc6006f0 pgd = (ptrval) [fc6006f0] *pgd=80000040207003, *pmd=00000000 Internal error: Oops: a06 [#1] SMP ARM Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 5.11.0+ #382 Hardware name: Generic DT based system PC is at cpu_ca15_set_pte_ext+0x24/0x30 LR is at __set_fixmap+0xe4/0x118 pc : [] lr : [] psr: 400000d3 sp : c1601ed8 ip : 00400000 fp : 00800000 r10: 0000071f r9 : 00421000 r8 : 00c00000 r7 : 00c00000 r6 : 0000071f r5 : ffade000 r4 : 4040171f r3 : 00c00000 r2 : 4040171f r1 : c041ac78 r0 : fc6006f0 Flags: nZcv IRQs off FIQs off Mode SVC_32 ISA ARM Segment none Control: 30c5387d Table: 40203000 DAC: 00000001 Process swapper (pid: 0, stack limit = 0x(ptrval)) So let's limit CONFIG_NR_CPUS to 16 when CONFIG_DEBUG_KMAP_LOCAL=y. Also, fix the BUILD_BUG_ON() check that was supposed to catch this, by checking whether the region grows below the start address rather than above the end address. Fixes: 2a15ba82fa6ca3f3 ("ARM: highmem: Switch to generic kmap atomic") Reported-by: Peter Robinson Tested-by: Peter Robinson Signed-off-by: Ard Biesheuvel Acked-by: Thomas Gleixner Reviewed-by: Linus Walleij Signed-off-by: Russell King --- arch/arm/Kconfig | 8 +++++++- arch/arm/mm/mmu.c | 3 +-- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 853aab5ab327..becc6d684051 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1292,9 +1292,15 @@ config KASAN_SHADOW_OFFSET config NR_CPUS int "Maximum number of CPUs (2-32)" - range 2 32 + range 2 16 if DEBUG_KMAP_LOCAL + range 2 32 if !DEBUG_KMAP_LOCAL depends on SMP default "4" + help + The maximum number of CPUs that the kernel can support. + Up to 32 CPUs can be supported, or up to 16 if kmap_local() + debugging is enabled, which uses half of the per-CPU fixmap + slots as guard regions. config HOTPLUG_CPU bool "Support for hot-pluggable CPUs" diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index a25b660c3017..c1e12aab67b8 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -387,8 +387,7 @@ void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot) pte_t *pte = pte_offset_fixmap(pmd_off_k(vaddr), vaddr); /* Make sure fixmap region does not exceed available allocation. */ - BUILD_BUG_ON(FIXADDR_START + (__end_of_fixed_addresses * PAGE_SIZE) > - FIXADDR_END); + BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) < FIXADDR_START); BUG_ON(idx >= __end_of_fixed_addresses); /* we only support device mappings until pgprot_kernel has been set */ From 45c2f70cba3a7eff34574103b2e2b901a5f771aa Mon Sep 17 00:00:00 2001 From: Vladimir Murzin Date: Thu, 11 Mar 2021 13:32:16 +0100 Subject: [PATCH 2/4] ARM: 9069/1: NOMMU: Fix conversion for_each_membock() to for_each_mem_range() for_each_mem_range() uses a loop variable, yet looking into code it is not just iteration counter but more complex entity which encodes information about memblock. Thus condition i == 0 looks fragile. Indeed, it broke boot of R-class platforms since it never took i == 0 path (due to i was set to 1). Fix that with restoring original flag check. Fixes: b10d6bca8720 ("arch, drivers: replace for_each_membock() with for_each_mem_range()") Signed-off-by: Vladimir Murzin Acked-by: Mike Rapoport Signed-off-by: Russell King --- arch/arm/mm/pmsa-v7.c | 4 +++- arch/arm/mm/pmsa-v8.c | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/arm/mm/pmsa-v7.c b/arch/arm/mm/pmsa-v7.c index 88950e41a3a9..59d916ccdf25 100644 --- a/arch/arm/mm/pmsa-v7.c +++ b/arch/arm/mm/pmsa-v7.c @@ -235,6 +235,7 @@ void __init pmsav7_adjust_lowmem_bounds(void) phys_addr_t mem_end; phys_addr_t reg_start, reg_end; unsigned int mem_max_regions; + bool first = true; int num; u64 i; @@ -263,7 +264,7 @@ void __init pmsav7_adjust_lowmem_bounds(void) #endif for_each_mem_range(i, ®_start, ®_end) { - if (i == 0) { + if (first) { phys_addr_t phys_offset = PHYS_OFFSET; /* @@ -275,6 +276,7 @@ void __init pmsav7_adjust_lowmem_bounds(void) mem_start = reg_start; mem_end = reg_end; specified_mem_size = mem_end - mem_start; + first = false; } else { /* * memblock auto merges contiguous blocks, remove diff --git a/arch/arm/mm/pmsa-v8.c b/arch/arm/mm/pmsa-v8.c index 2de019f7503e..8359748a19a1 100644 --- a/arch/arm/mm/pmsa-v8.c +++ b/arch/arm/mm/pmsa-v8.c @@ -95,10 +95,11 @@ void __init pmsav8_adjust_lowmem_bounds(void) { phys_addr_t mem_end; phys_addr_t reg_start, reg_end; + bool first = true; u64 i; for_each_mem_range(i, ®_start, ®_end) { - if (i == 0) { + if (first) { phys_addr_t phys_offset = PHYS_OFFSET; /* @@ -107,6 +108,7 @@ void __init pmsav8_adjust_lowmem_bounds(void) if (reg_start != phys_offset) panic("First memory bank must be contiguous from PHYS_OFFSET"); mem_end = reg_end; + first = false; } else { /* * memblock auto merges contiguous blocks, remove From 30e3b4f256b4e366a61658c294f6a21b8626dda7 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 25 Mar 2021 10:26:21 +0000 Subject: [PATCH 3/4] ARM: footbridge: fix PCI interrupt mapping Since commit 30fdfb929e82 ("PCI: Add a call to pci_assign_irq() in pci_device_probe()"), the PCI code will call the IRQ mapping function whenever a PCI driver is probed. If these are marked as __init, this causes an oops if a PCI driver is loaded or bound after the kernel has initialised. Fixes: 30fdfb929e82 ("PCI: Add a call to pci_assign_irq() in pci_device_probe()") Signed-off-by: Russell King --- arch/arm/mach-footbridge/cats-pci.c | 4 ++-- arch/arm/mach-footbridge/ebsa285-pci.c | 4 ++-- arch/arm/mach-footbridge/netwinder-pci.c | 2 +- arch/arm/mach-footbridge/personal-pci.c | 5 ++--- 4 files changed, 7 insertions(+), 8 deletions(-) diff --git a/arch/arm/mach-footbridge/cats-pci.c b/arch/arm/mach-footbridge/cats-pci.c index 0b2fd7e2e9b4..90b1e9be430e 100644 --- a/arch/arm/mach-footbridge/cats-pci.c +++ b/arch/arm/mach-footbridge/cats-pci.c @@ -15,14 +15,14 @@ #include /* cats host-specific stuff */ -static int irqmap_cats[] __initdata = { IRQ_PCI, IRQ_IN0, IRQ_IN1, IRQ_IN3 }; +static int irqmap_cats[] = { IRQ_PCI, IRQ_IN0, IRQ_IN1, IRQ_IN3 }; static u8 cats_no_swizzle(struct pci_dev *dev, u8 *pin) { return 0; } -static int __init cats_map_irq(const struct pci_dev *dev, u8 slot, u8 pin) +static int cats_map_irq(const struct pci_dev *dev, u8 slot, u8 pin) { if (dev->irq >= 255) return -1; /* not a valid interrupt. */ diff --git a/arch/arm/mach-footbridge/ebsa285-pci.c b/arch/arm/mach-footbridge/ebsa285-pci.c index 6f28aaa9ca79..c3f280d08fa7 100644 --- a/arch/arm/mach-footbridge/ebsa285-pci.c +++ b/arch/arm/mach-footbridge/ebsa285-pci.c @@ -14,9 +14,9 @@ #include #include -static int irqmap_ebsa285[] __initdata = { IRQ_IN3, IRQ_IN1, IRQ_IN0, IRQ_PCI }; +static int irqmap_ebsa285[] = { IRQ_IN3, IRQ_IN1, IRQ_IN0, IRQ_PCI }; -static int __init ebsa285_map_irq(const struct pci_dev *dev, u8 slot, u8 pin) +static int ebsa285_map_irq(const struct pci_dev *dev, u8 slot, u8 pin) { if (dev->vendor == PCI_VENDOR_ID_CONTAQ && dev->device == PCI_DEVICE_ID_CONTAQ_82C693) diff --git a/arch/arm/mach-footbridge/netwinder-pci.c b/arch/arm/mach-footbridge/netwinder-pci.c index 9473aa0305e5..e8304392074b 100644 --- a/arch/arm/mach-footbridge/netwinder-pci.c +++ b/arch/arm/mach-footbridge/netwinder-pci.c @@ -18,7 +18,7 @@ * We now use the slot ID instead of the device identifiers to select * which interrupt is routed where. */ -static int __init netwinder_map_irq(const struct pci_dev *dev, u8 slot, u8 pin) +static int netwinder_map_irq(const struct pci_dev *dev, u8 slot, u8 pin) { switch (slot) { case 0: /* host bridge */ diff --git a/arch/arm/mach-footbridge/personal-pci.c b/arch/arm/mach-footbridge/personal-pci.c index 4391e433a4b2..9d19aa98a663 100644 --- a/arch/arm/mach-footbridge/personal-pci.c +++ b/arch/arm/mach-footbridge/personal-pci.c @@ -14,13 +14,12 @@ #include #include -static int irqmap_personal_server[] __initdata = { +static int irqmap_personal_server[] = { IRQ_IN0, IRQ_IN1, IRQ_IN2, IRQ_IN3, 0, 0, 0, IRQ_DOORBELLHOST, IRQ_DMA1, IRQ_DMA2, IRQ_PCI }; -static int __init personal_server_map_irq(const struct pci_dev *dev, u8 slot, - u8 pin) +static int personal_server_map_irq(const struct pci_dev *dev, u8 slot, u8 pin) { unsigned char line; From d2f7eca60b29006285d57c7035539e33300e89e5 Mon Sep 17 00:00:00 2001 From: Fredrik Strupe Date: Mon, 5 Apr 2021 21:52:05 +0100 Subject: [PATCH 4/4] ARM: 9071/1: uprobes: Don't hook on thumb instructions Since uprobes is not supported for thumb, check that the thumb bit is not set when matching the uprobes instruction hooks. The Arm UDF instructions used for uprobes triggering (UPROBE_SWBP_ARM_INSN and UPROBE_SS_ARM_INSN) coincidentally share the same encoding as a pair of unallocated 32-bit thumb instructions (not UDF) when the condition code is 0b1111 (0xf). This in effect makes it possible to trigger the uprobes functionality from thumb, and at that using two unallocated instructions which are not permanently undefined. Signed-off-by: Fredrik Strupe Cc: stable@vger.kernel.org Fixes: c7edc9e326d5 ("ARM: add uprobes support") Signed-off-by: Russell King --- arch/arm/probes/uprobes/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/probes/uprobes/core.c b/arch/arm/probes/uprobes/core.c index c4b49b322e8a..f5f790c6e5f8 100644 --- a/arch/arm/probes/uprobes/core.c +++ b/arch/arm/probes/uprobes/core.c @@ -204,7 +204,7 @@ unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) static struct undef_hook uprobes_arm_break_hook = { .instr_mask = 0x0fffffff, .instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff), - .cpsr_mask = MODE_MASK, + .cpsr_mask = (PSR_T_BIT | MODE_MASK), .cpsr_val = USR_MODE, .fn = uprobe_trap_handler, }; @@ -212,7 +212,7 @@ static struct undef_hook uprobes_arm_break_hook = { static struct undef_hook uprobes_arm_ss_hook = { .instr_mask = 0x0fffffff, .instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff), - .cpsr_mask = MODE_MASK, + .cpsr_mask = (PSR_T_BIT | MODE_MASK), .cpsr_val = USR_MODE, .fn = uprobe_trap_handler, };