From 163e76cc6ef43b7a5e9b6e245a6d6667c9d9b4a7 Mon Sep 17 00:00:00 2001 From: Guo Ren Date: Tue, 13 Jun 2023 21:30:16 -0400 Subject: riscv: stack: Support HAVE_IRQ_EXIT_ON_IRQ_STACK MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add independent irq stacks for percpu to prevent kernel stack overflows. It is also compatible with VMAP_STACK by arch_alloc_vmap_stack. Tested-by: Jisheng Zhang Signed-off-by: Guo Ren Signed-off-by: Guo Ren Cc: Clément Léger Link: https://lore.kernel.org/r/20230614013018.2168426-2-guoren@kernel.org Signed-off-by: Palmer Dabbelt --- arch/riscv/Kconfig | 7 +++++++ arch/riscv/include/asm/irq_stack.h | 30 ++++++++++++++++++++++++++++++ arch/riscv/include/asm/thread_info.h | 2 ++ arch/riscv/kernel/irq.c | 33 +++++++++++++++++++++++++++++++++ arch/riscv/kernel/traps.c | 35 +++++++++++++++++++++++++++++++++-- 5 files changed, 105 insertions(+), 2 deletions(-) create mode 100644 arch/riscv/include/asm/irq_stack.h (limited to 'arch/riscv') diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index a3d54cd14fca..a8368fe7be14 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -590,6 +590,13 @@ config FPU If you don't know what to do here, say Y. +config IRQ_STACKS + bool "Independent irq stacks" if EXPERT + default y + select HAVE_IRQ_EXIT_ON_IRQ_STACK + help + Add independent irq stacks for percpu to prevent kernel stack overflows. + endmenu # "Platform type" menu "Kernel features" diff --git a/arch/riscv/include/asm/irq_stack.h b/arch/riscv/include/asm/irq_stack.h new file mode 100644 index 000000000000..e4042d297580 --- /dev/null +++ b/arch/riscv/include/asm/irq_stack.h @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_RISCV_IRQ_STACK_H +#define _ASM_RISCV_IRQ_STACK_H + +#include +#include +#include +#include +#include +#include + +DECLARE_PER_CPU(ulong *, irq_stack_ptr); + +#ifdef CONFIG_VMAP_STACK +/* + * To ensure that VMAP'd stack overflow detection works correctly, all VMAP'd + * stacks need to have the same alignment. + */ +static inline unsigned long *arch_alloc_vmap_stack(size_t stack_size, int node) +{ + void *p; + + p = __vmalloc_node(stack_size, THREAD_ALIGN, THREADINFO_GFP, node, + __builtin_return_address(0)); + return kasan_reset_tag(p); +} +#endif /* CONFIG_VMAP_STACK */ + +#endif /* _ASM_RISCV_IRQ_STACK_H */ diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h index 97e6f65ec176..2f32875276b0 100644 --- a/arch/riscv/include/asm/thread_info.h +++ b/arch/riscv/include/asm/thread_info.h @@ -40,6 +40,8 @@ #define OVERFLOW_STACK_SIZE SZ_4K #define SHADOW_OVERFLOW_STACK_SIZE (1024) +#define IRQ_STACK_SIZE THREAD_SIZE + #ifndef __ASSEMBLY__ extern long shadow_stack[SHADOW_OVERFLOW_STACK_SIZE / sizeof(long)]; diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c index eb9a68a539e6..a1dcf8e43b3c 100644 --- a/arch/riscv/kernel/irq.c +++ b/arch/riscv/kernel/irq.c @@ -28,6 +28,38 @@ struct fwnode_handle *riscv_get_intc_hwnode(void) } EXPORT_SYMBOL_GPL(riscv_get_intc_hwnode); +#ifdef CONFIG_IRQ_STACKS +#include + +DEFINE_PER_CPU(ulong *, irq_stack_ptr); + +#ifdef CONFIG_VMAP_STACK +static void init_irq_stacks(void) +{ + int cpu; + ulong *p; + + for_each_possible_cpu(cpu) { + p = arch_alloc_vmap_stack(IRQ_STACK_SIZE, cpu_to_node(cpu)); + per_cpu(irq_stack_ptr, cpu) = p; + } +} +#else +/* irq stack only needs to be 16 byte aligned - not IRQ_STACK_SIZE aligned. */ +DEFINE_PER_CPU_ALIGNED(ulong [IRQ_STACK_SIZE/sizeof(ulong)], irq_stack); + +static void init_irq_stacks(void) +{ + int cpu; + + for_each_possible_cpu(cpu) + per_cpu(irq_stack_ptr, cpu) = per_cpu(irq_stack, cpu); +} +#endif /* CONFIG_VMAP_STACK */ +#else +static void init_irq_stacks(void) {} +#endif /* CONFIG_IRQ_STACKS */ + int arch_show_interrupts(struct seq_file *p, int prec) { show_ipi_stats(p, prec); @@ -36,6 +68,7 @@ int arch_show_interrupts(struct seq_file *p, int prec) void __init init_IRQ(void) { + init_irq_stacks(); irqchip_init(); if (!handle_arch_irq) panic("No interrupt controller found."); diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 05ffdcd1424e..5158961ea977 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -27,6 +27,7 @@ #include #include #include +#include int show_unhandled_signals = 1; @@ -327,16 +328,46 @@ asmlinkage __visible noinstr void do_page_fault(struct pt_regs *regs) } #endif -asmlinkage __visible noinstr void do_irq(struct pt_regs *regs) +static void noinstr handle_riscv_irq(struct pt_regs *regs) { struct pt_regs *old_regs; - irqentry_state_t state = irqentry_enter(regs); irq_enter_rcu(); old_regs = set_irq_regs(regs); handle_arch_irq(regs); set_irq_regs(old_regs); irq_exit_rcu(); +} + +asmlinkage void noinstr do_irq(struct pt_regs *regs) +{ + irqentry_state_t state = irqentry_enter(regs); +#ifdef CONFIG_IRQ_STACKS + if (on_thread_stack()) { + ulong *sp = per_cpu(irq_stack_ptr, smp_processor_id()) + + IRQ_STACK_SIZE/sizeof(ulong); + __asm__ __volatile( + "addi sp, sp, -"RISCV_SZPTR "\n" + REG_S" ra, (sp) \n" + "addi sp, sp, -"RISCV_SZPTR "\n" + REG_S" s0, (sp) \n" + "addi s0, sp, 2*"RISCV_SZPTR "\n" + "move sp, %[sp] \n" + "move a0, %[regs] \n" + "call handle_riscv_irq \n" + "addi sp, s0, -2*"RISCV_SZPTR"\n" + REG_L" s0, (sp) \n" + "addi sp, sp, "RISCV_SZPTR "\n" + REG_L" ra, (sp) \n" + "addi sp, sp, "RISCV_SZPTR "\n" + : + : [sp] "r" (sp), [regs] "r" (regs) + : "a0", "a1", "a2", "a3", "a4", "a5", "a6", "a7", + "t0", "t1", "t2", "t3", "t4", "t5", "t6", + "memory"); + } else +#endif + handle_riscv_irq(regs); irqentry_exit(regs, state); } -- cgit v1.2.3