On Mon, May 20, 2019 at 10:20:02AM -0400, Steven Rostedt wrote:
> +#define FGRAPH_RET_SIZE (sizeof(struct ftrace_ret_stack))
> +#define FGRAPH_RET_INDEX (ALIGN(FGRAPH_RET_SIZE, sizeof(long)) /
> sizeof(long))
I think you want to write that like:
BUILD_BUG_ON(sizeof(ftrace_ret_stack) % sizeof(long));
It'd be very weird for that sizeof not to be right.
> +#define SHADOW_STACK_SIZE (PAGE_SIZE)
Do we really need that big a shadow stack?
> +#define SHADOW_STACK_INDEX \
> + (ALIGN(SHADOW_STACK_SIZE, sizeof(long)) / sizeof(long))
> +/* Leave on a buffer at the end */
> +#define SHADOW_STACK_MAX_INDEX (SHADOW_STACK_INDEX - FGRAPH_RET_INDEX)
> +
> +#define RET_STACK(t, index) ((struct ftrace_ret_stack
> *)(&(t)->ret_stack[index]))
> +#define RET_STACK_INC(c) ({ c += FGRAPH_RET_INDEX; })
> +#define RET_STACK_DEC(c) ({ c -= FGRAPH_RET_INDEX; })
I'm thinking something like:
#define RET_PUSH(s, val) \
do { \
(s) -= sizeof(val); \
(typeof(val) *)(s) = val; \
} while (0)
#define RET_POP(s, type) \
({ \
type *__ptr = (void *)(s); \
(s) += sizeof(type); \
*__ptr; \
})
Would me clearer?
