Aksal/nuttx
3
1
Fork 1
mirror of https://github.com/apache/nuttx.git synced 2026-08-10 15:05:07 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 2

arch/risc-v: kill faulting user task instead of panicking kernel

Browse source 
riscv_fillpage() unconditionally panics the kernel on an unmappable
or invalid access, even when the fault is caused by a user task. A
user-space fault should terminate that task with SIGSEGV instead of
taking down the whole system, matching the existing behavior for
other exceptions in riscv_exception().

Signed-off-by: liang.huang <liang.huang@houmo.ai>
This commit is contained in:
liang.huang 2026-07-09 11:32:03 +08:00 • committed by Xiang Xiao
parent 6bfb85c96f
commit 41837f0699
1 changed files with 42 additions and 24 deletions
Download patch file Download diff file Expand all files Collapse all files

66
arch/risc-v/src/common/riscv_exception.c
View file

@ -83,26 +83,27 @@ static const char *g_reasons_str[RISCV_MAX_EXCEPTION + 1] =
****************************************************************************/
/****************************************************************************
* Name: riscv_exception
* Name: riscv_fault_handler
*
* Description:
* This is the exception handler.
* Handle a fault caused by the running task. If the task is a user task
* not currently in a syscall, kill it with SIGSEGV instead of
* taking down the whole system. Otherwise (kernel thread, or a fault
* while already in kernel context on behalf of a syscall) there is no
* safe task to kill, so panic.
*
* Input Parameters:
* cause - The (masked) machine cause of the exception, used for the
* panic message only.
* regs - A pointer to the register state at the time of the exception.
*
****************************************************************************/
int riscv_exception(int mcause, void *regs, void *args)
static void riscv_fault_handler(uintreg_t cause, void *regs)
{
#ifdef CONFIG_ARCH_KERNEL_STACK
struct tcb_s *tcb = this_task();
#endif
uintreg_t cause = mcause & RISCV_IRQ_MASK;
_alert("EXCEPTION: %s. MCAUSE: %" PRIxREG ", EPC: %" PRIxREG
", MTVAL: %" PRIxREG "\n",
mcause > RISCV_MAX_EXCEPTION ? "Unknown" : g_reasons_str[cause],
cause, READ_CSR(CSR_EPC), READ_CSR(CSR_TVAL));
#ifdef CONFIG_ARCH_KERNEL_STACK
if (((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL) &&
((tcb->flags & TCB_FLAG_SYSCALL) == false))
{
@ -124,15 +125,34 @@ int riscv_exception(int mcause, void *regs, void *args)
*/
running_regs()[REG_SP] = tcb->xcp.ktopstk;
return;
}
else
#endif
{
_alert("PANIC!!! Exception = %" PRIxREG "\n", cause);
up_irq_save();
up_set_interrupt_context(true);
PANIC_WITH_REGS("panic", regs);
}
_alert("PANIC!!! Exception = %" PRIxREG "\n", cause);
up_irq_save();
up_set_interrupt_context(true);
PANIC_WITH_REGS("panic", regs);
}
/****************************************************************************
* Name: riscv_exception
*
* Description:
* This is the exception handler.
*
****************************************************************************/
int riscv_exception(int mcause, void *regs, void *args)
{
uintreg_t cause = mcause & RISCV_IRQ_MASK;
_alert("EXCEPTION: %s. MCAUSE: %" PRIxREG ", EPC: %" PRIxREG
", MTVAL: %" PRIxREG "\n",
mcause > RISCV_MAX_EXCEPTION ? "Unknown" : g_reasons_str[cause],
cause, READ_CSR(CSR_EPC), READ_CSR(CSR_TVAL));
riscv_fault_handler(cause, regs);
return 0;
}
@ -200,7 +220,7 @@ int riscv_fillpage(int mcause, void *regs, void *args)
}
else
{
_alert("PANIC!!! virtual address not mappable: %" PRIxPTR "\n", vaddr);
_alert("Virtual address not mappable: %" PRIxPTR "\n", vaddr);
goto access_fault;
}
@ -242,7 +262,7 @@ int riscv_fillpage(int mcause, void *regs, void *args)
if (mmu_ln_getentry(ARCH_PGT_MAX_LEVELS, ptlast, vaddr) & PTE_VALID)
{
_alert("PANIC!!! page already mapped, permission violation: %"
_alert("Page already mapped, permission violation: %"
PRIxPTR "\n", vaddr);
goto access_fault;
}
@ -264,10 +284,8 @@ int riscv_fillpage(int mcause, void *regs, void *args)
return 0;
access_fault:
up_irq_save();
up_set_interrupt_context(true);
PANIC_WITH_REGS("panic", regs);
return -EINVAL;
riscv_fault_handler(cause, regs);
return 0;
}
#endif /* CONFIG_PAGING */