From 6a91f64ee12fe54d1a9573e9ecbbae037b113097 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 29 Jul 2025 09:13:54 -1000 Subject: linux-user: Move init_guest_commpage to hppa/elfload.c Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson --- linux-user/hppa/elfload.c | 31 +++++++++++++++++++++++++++++++ linux-user/hppa/target_elf.h | 2 ++ 2 files changed, 33 insertions(+) (limited to 'linux-user/hppa') diff --git a/linux-user/hppa/elfload.c b/linux-user/hppa/elfload.c index 9dd3fe0..018034f 100644 --- a/linux-user/hppa/elfload.c +++ b/linux-user/hppa/elfload.c @@ -3,6 +3,7 @@ #include "qemu/osdep.h" #include "qemu.h" #include "loader.h" +#include "target_elf.h" const char *get_elf_cpu_model(uint32_t eflags) @@ -14,3 +15,33 @@ const char *get_elf_platform(CPUState *cs) { return "PARISC"; } + +bool init_guest_commpage(void) +{ + /* If reserved_va, then we have already mapped 0 page on the host. */ + if (!reserved_va) { + void *want, *addr; + + want = g2h_untagged(LO_COMMPAGE); + addr = mmap(want, TARGET_PAGE_SIZE, PROT_NONE, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED_NOREPLACE, -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_MASK, + PAGE_EXEC | PAGE_VALID); + return true; +} diff --git a/linux-user/hppa/target_elf.h b/linux-user/hppa/target_elf.h index 85be005..b654758 100644 --- a/linux-user/hppa/target_elf.h +++ b/linux-user/hppa/target_elf.h @@ -10,4 +10,6 @@ #define HAVE_ELF_PLATFORM 1 +#define LO_COMMPAGE 0 + #endif -- cgit v1.1