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riscv: Use separate IRQ shadow call stacks 

When both CONFIG_IRQ_STACKS and SCS are enabled, also use a separate
per-CPU shadow call stack.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20230927224757.1154247-13-samitolvanen@google.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Sami Tolvanen 2023-09-27 22:48:03 +00:00 committed by Palmer Dabbelt
parent d1584d791a
commit c40fef858d
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
3 changed files with 35 additions and 0 deletions
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7
arch/riscv/include/asm/scs.h
View File

@ -13,6 +13,11 @@
XIP_FIXUP_OFFSET gp
.endm
/* Load the per-CPU IRQ shadow call stack to gp. */
.macro scs_load_irq_stack tmp
load_per_cpu gp, irq_shadow_call_stack_ptr, \tmp
.endm
/* Load task_scs_sp(current) to gp. */
.macro scs_load_current
REG_L gp, TASK_TI_SCS_SP(tp)
@ -34,6 +39,8 @@ _skip_scs:
.macro scs_load_init_stack
.endm
.macro scs_load_irq_stack tmp
.endm
.macro scs_load_current
.endm
.macro scs_load_current_if_task_changed prev

7
arch/riscv/kernel/entry.S
View File

@ -237,12 +237,19 @@ SYM_FUNC_START(call_on_irq_stack)
REG_S s0, STACKFRAME_FP(sp)
addi s0, sp, STACKFRAME_SIZE_ON_STACK
/* Switch to the per-CPU shadow call stack */
scs_save_current
scs_load_irq_stack t0
/* Switch to the per-CPU IRQ stack and call the handler */
load_per_cpu t0, irq_stack_ptr, t1
li t1, IRQ_STACK_SIZE
add sp, t0, t1
jalr a1
/* Switch back to the thread shadow call stack */
scs_load_current
/* Switch back to the thread stack and restore ra and s0 */
addi sp, s0, -STACKFRAME_SIZE_ON_STACK
REG_L ra, STACKFRAME_RA(sp)

21
arch/riscv/kernel/irq.c
View File

@ -9,6 +9,7 @@
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/scs.h>
#include <linux/seq_file.h>
#include <asm/sbi.h>
#include <asm/smp.h>
@ -34,6 +35,24 @@ EXPORT_SYMBOL_GPL(riscv_get_intc_hwnode);
#ifdef CONFIG_IRQ_STACKS
#include <asm/irq_stack.h>
DECLARE_PER_CPU(ulong *, irq_shadow_call_stack_ptr);
#ifdef CONFIG_SHADOW_CALL_STACK
DEFINE_PER_CPU(ulong *, irq_shadow_call_stack_ptr);
#endif
static void init_irq_scs(void)
{
int cpu;
if (!scs_is_enabled())
return;
for_each_possible_cpu(cpu)
per_cpu(irq_shadow_call_stack_ptr, cpu) =
scs_alloc(cpu_to_node(cpu));
}
DEFINE_PER_CPU(ulong *, irq_stack_ptr);
#ifdef CONFIG_VMAP_STACK
@ -76,6 +95,7 @@ void do_softirq_own_stack(void)
#endif /* CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK */
#else
static void init_irq_scs(void) {}
static void init_irq_stacks(void) {}
#endif /* CONFIG_IRQ_STACKS */
@ -87,6 +107,7 @@ int arch_show_interrupts(struct seq_file *p, int prec)
void __init init_IRQ(void)
{
init_irq_scs();
init_irq_stacks();
irqchip_init();
if (!handle_arch_irq)