diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2023-03-06 01:26:29 +0300 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2023-03-28 15:23:10 -0700 |
| commit | 95059f9c313a7fbd7f22e4cdc1977c0393addc7b (patch) | |
| tree | 5cbda761db3d946f2dafca04afaab139077596dd /linux-user/main.c | |
| parent | a3a67f54f0b4ec98ff2380a792e5bfeebc47d554 (diff) | |
include/exec: Change reserved_va semantics to last byte
Change the semantics to be the last byte of the guest va, rather
than the following byte. This avoids some overflow conditions.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'linux-user/main.c')
| -rw-r--r-- | linux-user/main.c | 27 |
1 files changed, 13 insertions, 14 deletions
diff --git a/linux-user/main.c b/linux-user/main.c index 39d9bd4d7a..fe03293516 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -109,11 +109,9 @@ static const char *last_log_filename; # if HOST_LONG_BITS > TARGET_VIRT_ADDR_SPACE_BITS # if TARGET_VIRT_ADDR_SPACE_BITS == 32 && \ (TARGET_LONG_BITS == 32 || defined(TARGET_ABI32)) -/* There are a number of places where we assign reserved_va to a variable - of type abi_ulong and expect it to fit. Avoid the last page. */ -# define MAX_RESERVED_VA(CPU) (0xfffffffful & TARGET_PAGE_MASK) +# define MAX_RESERVED_VA(CPU) 0xfffffffful # else -# define MAX_RESERVED_VA(CPU) (1ul << TARGET_VIRT_ADDR_SPACE_BITS) +# define MAX_RESERVED_VA(CPU) ((1ul << TARGET_VIRT_ADDR_SPACE_BITS) - 1) # endif # else # define MAX_RESERVED_VA(CPU) 0 @@ -379,7 +377,9 @@ static void handle_arg_reserved_va(const char *arg) { char *p; int shift = 0; - reserved_va = strtoul(arg, &p, 0); + unsigned long val; + + val = strtoul(arg, &p, 0); switch (*p) { case 'k': case 'K': @@ -393,10 +393,10 @@ static void handle_arg_reserved_va(const char *arg) break; } if (shift) { - unsigned long unshifted = reserved_va; + unsigned long unshifted = val; p++; - reserved_va <<= shift; - if (reserved_va >> shift != unshifted) { + val <<= shift; + if (val >> shift != unshifted) { fprintf(stderr, "Reserved virtual address too big\n"); exit(EXIT_FAILURE); } @@ -405,6 +405,8 @@ static void handle_arg_reserved_va(const char *arg) fprintf(stderr, "Unrecognised -R size suffix '%s'\n", p); exit(EXIT_FAILURE); } + /* The representation is size - 1, with 0 remaining "default". */ + reserved_va = val ? val - 1 : 0; } static void handle_arg_singlestep(const char *arg) @@ -793,7 +795,7 @@ int main(int argc, char **argv, char **envp) */ max_reserved_va = MAX_RESERVED_VA(cpu); if (reserved_va != 0) { - if (reserved_va % qemu_host_page_size) { + if ((reserved_va + 1) % qemu_host_page_size) { char *s = size_to_str(qemu_host_page_size); fprintf(stderr, "Reserved virtual address not aligned mod %s\n", s); g_free(s); @@ -804,11 +806,8 @@ int main(int argc, char **argv, char **envp) exit(EXIT_FAILURE); } } else if (HOST_LONG_BITS == 64 && TARGET_VIRT_ADDR_SPACE_BITS <= 32) { - /* - * reserved_va must be aligned with the host page size - * as it is used with mmap() - */ - reserved_va = max_reserved_va & qemu_host_page_mask; + /* MAX_RESERVED_VA + 1 is a large power of 2, so is aligned. */ + reserved_va = max_reserved_va; } { |