linux/arch/x86/kernel/irq_64.c
Thomas Gleixner a7b3474cbb x86/irq: Make run_on_irqstack_cond() typesafe
Sami reported that run_on_irqstack_cond() requires the caller to cast
functions to mismatching types, which trips indirect call Control-Flow
Integrity (CFI) in Clang.

Instead of disabling CFI on that function, provide proper helpers for
the three call variants. The actual ASM code stays the same as that is
out of reach.

 [ bp: Fix __run_on_irqstack() prototype to match. ]

Fixes: 931b941459 ("x86/entry: Provide helpers for executing on the irqstack")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Reported-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Cc: <stable@vger.kernel.org>
Link: https://github.com/ClangBuiltLinux/linux/issues/1052
Link: https://lkml.kernel.org/r/87pn6eb5tv.fsf@nanos.tec.linutronix.de
2020-09-22 22:13:34 +02:00

79 lines
1.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
*
* This file contains the lowest level x86_64-specific interrupt
* entry and irq statistics code. All the remaining irq logic is
* done by the generic kernel/irq/ code and in the
* x86_64-specific irq controller code. (e.g. i8259.c and
* io_apic.c.)
*/
#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/seq_file.h>
#include <linux/delay.h>
#include <linux/ftrace.h>
#include <linux/uaccess.h>
#include <linux/smp.h>
#include <linux/sched/task_stack.h>
#include <asm/cpu_entry_area.h>
#include <asm/irq_stack.h>
#include <asm/io_apic.h>
#include <asm/apic.h>
DEFINE_PER_CPU_PAGE_ALIGNED(struct irq_stack, irq_stack_backing_store) __visible;
DECLARE_INIT_PER_CPU(irq_stack_backing_store);
#ifdef CONFIG_VMAP_STACK
/*
* VMAP the backing store with guard pages
*/
static int map_irq_stack(unsigned int cpu)
{
char *stack = (char *)per_cpu_ptr(&irq_stack_backing_store, cpu);
struct page *pages[IRQ_STACK_SIZE / PAGE_SIZE];
void *va;
int i;
for (i = 0; i < IRQ_STACK_SIZE / PAGE_SIZE; i++) {
phys_addr_t pa = per_cpu_ptr_to_phys(stack + (i << PAGE_SHIFT));
pages[i] = pfn_to_page(pa >> PAGE_SHIFT);
}
va = vmap(pages, IRQ_STACK_SIZE / PAGE_SIZE, VM_MAP, PAGE_KERNEL);
if (!va)
return -ENOMEM;
per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE;
return 0;
}
#else
/*
* If VMAP stacks are disabled due to KASAN, just use the per cpu
* backing store without guard pages.
*/
static int map_irq_stack(unsigned int cpu)
{
void *va = per_cpu_ptr(&irq_stack_backing_store, cpu);
per_cpu(hardirq_stack_ptr, cpu) = va + IRQ_STACK_SIZE;
return 0;
}
#endif
int irq_init_percpu_irqstack(unsigned int cpu)
{
if (per_cpu(hardirq_stack_ptr, cpu))
return 0;
return map_irq_stack(cpu);
}
void do_softirq_own_stack(void)
{
run_on_irqstack_cond(__do_softirq, NULL);
}