Commit 26d75ab7 authored by Yong Cong Sin's avatar Yong Cong Sin Committed by Carles Cufi
Browse files

arch: riscv: optionally stores a pointer to csf in `struct arch_esf` 



The callee-saved-registers can be helpful to debug the state of
a core upon an exception, however, currently there's no way to
access that information in user-implemented
`k_sys_fatal_error_handler()`, even though the csf is already stored
in the stack.

This patch conditionally add a `csf` member in the `arch_esf` when
`CONFIG_EXTRA_EXCEPTION_INFO=y`*, which the `_isr_wrapper` would update
when a fatal error occurs before invoking `z_riscv_fatal_error_csf()`.

Functions such as `k_sys_fatal_error_handler()` would then be able
to access the callee-saved-registers at the time of exception via
`esf->csf`.

* For SoCs that select `RISCV_SOC_HAS_ISR_STACKING`, the
  `SOC_ISR_STACKING_ESF_DECLARE` has to include the `csf` member,
  otherwise the build would fail.

Signed-off-by: default avatarYong Cong Sin <ycsin@meta.com>
Signed-off-by: default avatarYong Cong Sin <yongcong.sin@gmail.com>
parent 19682208

arch/riscv/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -238,6 +238,14 @@ config RISCV_HART_MASK 
	  i.e. 128, 129, ..(0x80, 8x81, ..), this can be configured to 63 (0x7f)

	  such that we can extract the bits that start from 0.



config EXTRA_EXCEPTION_INFO

	bool "Collect extra exception info"

	depends on EXCEPTION_DEBUG

	help

	  This option enables the collection of extra information, such as

	  register state, when a fault occurs. This information can be useful

	  to collect for post-mortem analysis and debug of issues.



config RISCV_PMP

	bool "RISC-V PMP Support"

	select THREAD_STACK_INFO

arch/riscv/core/isr.S

+6 −1
Original line number Diff line number Diff line
@@ -450,10 +450,15 @@ do_fault: 
	STORE_CALLEE_SAVED()		;

	mv a2, sp



#ifdef CONFIG_EXTRA_EXCEPTION_INFO

	/* Store csf's addr into esf (a1 still holds the pointer to the esf at this point) */

	sr a2 __struct_arch_esf_csf_OFFSET(a1)

#endif /* CONFIG_EXTRA_EXCEPTION_INFO */



	tail z_riscv_fatal_error_csf

#else

	tail z_riscv_fatal_error

#endif

#endif /* CONFIG_EXCEPTION_DEBUG */



#if defined(CONFIG_IRQ_OFFLOAD)

do_irq_offload:

arch/riscv/core/offsets/offsets.c

+4 −0
Original line number Diff line number Diff line
@@ -118,6 +118,10 @@ GEN_OFFSET_STRUCT(arch_esf, s0); 
GEN_OFFSET_STRUCT(arch_esf, sp);

#endif



#ifdef CONFIG_EXTRA_EXCEPTION_INFO

GEN_OFFSET_STRUCT(arch_esf, csf);

#endif /* CONFIG_EXTRA_EXCEPTION_INFO */



#if defined(CONFIG_RISCV_SOC_CONTEXT_SAVE)

GEN_OFFSET_STRUCT(arch_esf, soc_context);

#endif

doc/releases/release-notes-4.0.rst

+7 −0
Original line number Diff line number Diff line
@@ -64,6 +64,13 @@ Architectures 
  * The stack traces upon fatal exception now prints the address of stack pointer (sp) or frame

    pointer (fp) depending on the build configuration.



  * When :kconfig:option:`CONFIG_EXTRA_EXCEPTION_INFO` is enabled, the exception stack frame (arch_esf)

    has an additional field ``csf`` that points to the callee-saved-registers upon an fatal error,

    which can be accessed in :c:func:`k_sys_fatal_error_handler` by ``esf->csf``.



    * For SoCs that select `RISCV_SOC_HAS_ISR_STACKING`, the `SOC_ISR_STACKING_ESF_DECLARE` has to

      include the `csf` member, otherwise the build would fail.



* Xtensa



* x86

include/zephyr/arch/riscv/exception.h

+10 −0
Original line number Diff line number Diff line
@@ -45,6 +45,12 @@ struct soc_esf { 
};

#endif



#ifdef CONFIG_EXTRA_EXCEPTION_INFO

/* Forward declaration */

struct _callee_saved;

typedef struct _callee_saved _callee_saved_t;

#endif /* CONFIG_EXTRA_EXCEPTION_INFO */



#if defined(CONFIG_RISCV_SOC_HAS_ISR_STACKING)

	SOC_ISR_STACKING_ESF_DECLARE;

#else
@@ -81,6 +87,10 @@ struct arch_esf { 
	unsigned long sp;		/* preserved (user or kernel) stack pointer */

#endif



#ifdef CONFIG_EXTRA_EXCEPTION_INFO

	_callee_saved_t *csf;		/* pointer to callee-saved-registers */

#endif /* CONFIG_EXTRA_EXCEPTION_INFO */



#ifdef CONFIG_RISCV_SOC_CONTEXT_SAVE

	struct soc_esf soc_context;

#endif

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