Richard Henderson <richard.hender...@linaro.org> writes:
> When PAGE_RESET is set, we are replacing pages with new
> content, which means that we need to invalidate existing
> cached data, such as TranslationBlocks. Perform the
> reset invalidate while we're doing other invalidates,
> which allows us to remove the separate invalidates from
> the user-only mmap/munmap/mprotect routines.
>
> In addition, restrict invalidation to PAGE_EXEC pages.
> Since cdf713085131, we have validated PAGE_EXEC is present
> before translation, which means we can assume that if the
> bit is not present, there are no translations to invalidate.
>
> Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
> ---
> accel/tcg/translate-all.c | 19 +++++++++++--------
> bsd-user/mmap.c | 2 --
> linux-user/mmap.c | 4 ----
> 3 files changed, 11 insertions(+), 14 deletions(-)
>
> diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
> index 8d5233fa9e..478301f227 100644
> --- a/accel/tcg/translate-all.c
> +++ b/accel/tcg/translate-all.c
> @@ -1352,7 +1352,7 @@ int page_get_flags(target_ulong address)
> void page_set_flags(target_ulong start, target_ulong end, int flags)
> {
> target_ulong addr, len;
> - bool reset_target_data;
> + bool reset;
>
> /* This function should never be called with addresses outside the
> guest address space. If this assert fires, it probably indicates
> @@ -1369,7 +1369,7 @@ void page_set_flags(target_ulong start, target_ulong
> end, int flags)
> if (flags & PAGE_WRITE) {
> flags |= PAGE_WRITE_ORG;
> }
> - reset_target_data = !(flags & PAGE_VALID) || (flags & PAGE_RESET);
> + reset = !(flags & PAGE_VALID) || (flags & PAGE_RESET);
> flags &= ~PAGE_RESET;
Not a problem with this patch but I was a little confused by PAGE_VALID
because its the one "special" flag not documented in cpu-all.h:
/* same as PROT_xxx */
#define PAGE_READ 0x0001
#define PAGE_WRITE 0x0002
#define PAGE_EXEC 0x0004
#define PAGE_BITS (PAGE_READ | PAGE_WRITE | PAGE_EXEC)
The above are self explanatory as they mirror the mmap flags. But what
does PAGE_VALID really mean. We set it in the elfloader and whenever we
mmap which begs the question when is a page not VALID? The only place
that ever seems to clear the flag is the PPC mmu_helper code in a
response to a particular TLB operations. Should that code instead be
doing page_set_flags(PAGE_RESET)?
#define PAGE_VALID 0x0008
/*
* Original state of the write flag (used when tracking self-modifying code)
*/
#define PAGE_WRITE_ORG 0x0010
/*
* Invalidate the TLB entry immediately, helpful for s390x
* Low-Address-Protection. Used with PAGE_WRITE in tlb_set_page_with_attrs()
*/
#define PAGE_WRITE_INV 0x0020
/* For use with page_set_flags: page is being replaced; target_data cleared.
*/
#define PAGE_RESET 0x0040
/* For linux-user, indicates that the page is MAP_ANON. */
#define PAGE_ANON 0x0080
#if defined(CONFIG_BSD) && defined(CONFIG_USER_ONLY)
/* FIXME: Code that sets/uses this is broken and needs to go away. */
#define PAGE_RESERVED 0x0100
#endif
/* Target-specific bits that will be used via page_get_flags(). */
#define PAGE_TARGET_1 0x0200
#define PAGE_TARGET_2 0x0400
/*
* For linux-user, indicates that the page is mapped with the same semantics
* in both guest and host.
*/
#define PAGE_PASSTHROUGH 0x0800
Anyway that confusion aside:
Reviewed-by: Alex Bennée <alex.ben...@linaro.org>
--
Alex Bennée
