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| author | Richard Henderson <richard.henderson@linaro.org> | 2022-08-10 18:44:48 -0700 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2022-09-06 07:32:35 +0100 |
| commit | eee816c0b972bd085e62fcd7d2de7a34dbbd155b (patch) | |
| tree | 76fd3d0e410e29232cc09a1f6e3d7af53b246e47 | |
| parent | fbd3c4cff641cae082edb765017cbb699efa6712 (diff) | |
| download | qemu-eee816c0b972bd085e62fcd7d2de7a34dbbd155b.zip qemu-eee816c0b972bd085e62fcd7d2de7a34dbbd155b.tar.gz qemu-eee816c0b972bd085e62fcd7d2de7a34dbbd155b.tar.bz2 | |
linux-user/hppa: Allocate page zero as a commpage
We're about to start validating PAGE_EXEC, which means that we've
got to mark page zero executable. We had been special casing this
entirely within translate.
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
| -rw-r--r-- | linux-user/elfload.c | 34 |
1 files changed, 31 insertions, 3 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 3e3dc02..29d910c 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -1646,6 +1646,34 @@ static inline void init_thread(struct target_pt_regs *regs, regs->gr[31] = infop->entry; } +#define LO_COMMPAGE 0 + +static bool init_guest_commpage(void) +{ + void *want = g2h_untagged(LO_COMMPAGE); + void *addr = mmap(want, qemu_host_page_size, PROT_NONE, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); + + if (addr == MAP_FAILED) { + perror("Allocating guest commpage"); + exit(EXIT_FAILURE); + } + if (addr != want) { + return false; + } + + /* + * On Linux, page zero is normally marked execute only + gateway. + * Normal read or write is supposed to fail (thus PROT_NONE above), + * but specific offsets have kernel code mapped to raise permissions + * and implement syscalls. Here, simply mark the page executable. + * Special case the entry points during translation (see do_page_zero). + */ + page_set_flags(LO_COMMPAGE, LO_COMMPAGE + TARGET_PAGE_SIZE, + PAGE_EXEC | PAGE_VALID); + return true; +} + #endif /* TARGET_HPPA */ #ifdef TARGET_XTENSA @@ -2326,12 +2354,12 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc, } #if defined(HI_COMMPAGE) -#define LO_COMMPAGE 0 +#define LO_COMMPAGE -1 #elif defined(LO_COMMPAGE) #define HI_COMMPAGE 0 #else #define HI_COMMPAGE 0 -#define LO_COMMPAGE 0 +#define LO_COMMPAGE -1 #define init_guest_commpage() true #endif @@ -2555,7 +2583,7 @@ static void pgb_static(const char *image_name, abi_ulong orig_loaddr, } else { offset = -(HI_COMMPAGE & -align); } - } else if (LO_COMMPAGE != 0) { + } else if (LO_COMMPAGE != -1) { loaddr = MIN(loaddr, LO_COMMPAGE & -align); } |