TOn 29/06/2017 20:46, Jim Mattson wrote:
> The default handler for #DE, #UD, and #GP is check_exception_table.
> Test_for_exception should restore the original handler before
> returning, rather than blindly clobbering it with NULL.
>
> Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
Thanks, series tested and applied.
Paolo
> ---
> lib/x86/desc.c | 16 ++++++++++------
> lib/x86/desc.h | 4 +++-
> 2 files changed, 13 insertions(+), 7 deletions(-)
>
> diff --git a/lib/x86/desc.c b/lib/x86/desc.c
> index 402204ddcac4..830c5d127dbc 100644
> --- a/lib/x86/desc.c
> +++ b/lib/x86/desc.c
> @@ -117,13 +117,16 @@ static void check_exception_table(struct ex_regs *regs)
> unhandled_exception(regs, false);
> }
>
> -static void (*exception_handlers[32])(struct ex_regs *regs);
> +static handler exception_handlers[32];
>
> -
> -void handle_exception(u8 v, void (*func)(struct ex_regs *regs))
> +handler handle_exception(u8 v, handler fn)
> {
> + handler old;
> +
> + old = exception_handlers[v];
> if (v < 32)
> - exception_handlers[v] = func;
> + exception_handlers[v] = fn;
> + return old;
> }
>
> #ifndef __x86_64__
> @@ -390,14 +393,15 @@ static void exception_handler(struct ex_regs *regs)
> bool test_for_exception(unsigned int ex, void (*trigger_func)(void *data),
> void *data)
> {
> + handler old;
> jmp_buf jmpbuf;
> int ret;
>
> - handle_exception(ex, exception_handler);
> + old = handle_exception(ex, exception_handler);
> ret = set_exception_jmpbuf(jmpbuf);
> if (ret == 0)
> trigger_func(data);
> - handle_exception(ex, NULL);
> + handle_exception(ex, old);
> return ret;
> }
>
> diff --git a/lib/x86/desc.h b/lib/x86/desc.h
> index be52fd4e1d92..a2500e0f6006 100644
> --- a/lib/x86/desc.h
> +++ b/lib/x86/desc.h
> @@ -20,6 +20,8 @@ struct ex_regs {
> unsigned long rflags;
> };
>
> +typedef void (*handler)(struct ex_regs *regs);
> +
> typedef struct {
> u16 prev;
> u16 res1;
> @@ -153,7 +155,7 @@ void set_idt_dpl(int vec, u16 dpl);
> void set_gdt_entry(int sel, u32 base, u32 limit, u8 access, u8 gran);
> void set_intr_alt_stack(int e, void *fn);
> void print_current_tss_info(void);
> -void handle_exception(u8 v, void (*func)(struct ex_regs *regs));
> +handler handle_exception(u8 v, handler fn);
>
> bool test_for_exception(unsigned int ex, void (*trigger_func)(void *data),
> void *data);
>
