diff options
Diffstat (limited to 'libre/qemu-user-static/0010-linux-user-init_guest_space-Try-to-make-ARM-space-co.patch')
| -rw-r--r-- | libre/qemu-user-static/0010-linux-user-init_guest_space-Try-to-make-ARM-space-co.patch | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/libre/qemu-user-static/0010-linux-user-init_guest_space-Try-to-make-ARM-space-co.patch b/libre/qemu-user-static/0010-linux-user-init_guest_space-Try-to-make-ARM-space-co.patch new file mode 100644 index 000000000..587293564 --- /dev/null +++ b/libre/qemu-user-static/0010-linux-user-init_guest_space-Try-to-make-ARM-space-co.patch @@ -0,0 +1,99 @@ +From f8ccd5e7353937e0a48ccd8bfbc07202dc85afac Mon Sep 17 00:00:00 2001 +From: Luke Shumaker <lukeshu@parabola.nu> +Date: Thu, 28 Dec 2017 07:27:20 -0500 +Cc: paul@codesourcery.com +Subject: [PATCH 10/10] linux-user: init_guest_space: Try to make ARM + space+commpage continuous + +At a fixed distance after the usable memory that init_guest_space maps, for +32-bit ARM targets we also need to map a commpage. The normal +init_guest_space logic doesn't keep this in mind when searching for an +address range. + +If !host_start, then try to find a big continuous segment where we can put +both the usable memory and the commpage; we then munmap that segment and +set current_start to that address; and let the normal code mmap the usable +memory and the commpage separately. That is: if we don't have hint of +where to start looking for memory, come up with one that is better than +NULL. Depending on host_size and guest_start, there may or may not be a +gap between the usable memory and the commpage, so this is slightly more +restrictive than it needs to be; but it's only a hint, so that's OK. + +We only do that for !host start, because if host_start, then either: + - we got an address passed in with -B, in which case we don't want to + interfere with what the user said; + - or host_start is based off of the ELF image's loaddr. The check "if + (host_start && real_start != current_start)" suggests that we really + want lowest available address that is >= loaddr. I don't know why that + is, but I'm trusting that Paul Brook knew what he was doing when he + wrote the original version of that check in + c581deda322080e8beb88b2e468d4af54454e4b3 way back in 2010. + +Signed-off-by: Luke Shumaker <lukeshu@parabola.nu> +--- + linux-user/elfload.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ + 1 file changed, 49 insertions(+) + +diff --git a/linux-user/elfload.c b/linux-user/elfload.c +index 7736ea2c3a..cd3a7d877d 100644 +--- a/linux-user/elfload.c ++++ b/linux-user/elfload.c +@@ -1857,6 +1857,55 @@ unsigned long init_guest_space(unsigned long host_start, + + /* Otherwise, a non-zero size region of memory needs to be mapped + * and validated. */ ++ ++#if defined(TARGET_ARM) && !defined(TARGET_AARCH64) ++ /* On 32-bit ARM, we need to map not just the usable memory, but ++ * also the commpage. Try to find a suitable place by allocating ++ * a big chunk for all of it. If host_start, then the naive ++ * strategy probably does good enough. ++ */ ++ if (!host_start) { ++ unsigned long guest_full_size, host_full_size, real_start; ++ ++ guest_full_size = ++ (0xffff0f00 & qemu_host_page_mask) + qemu_host_page_size; ++ host_full_size = guest_full_size - guest_start; ++ real_start = (unsigned long) ++ mmap(NULL, host_full_size, PROT_NONE, flags, -1, 0); ++ if (real_start == (unsigned long)-1) { ++ if (host_size < host_full_size - qemu_host_page_size) { ++ /* We failed to map a continous segment, but we're ++ * allowed to have a gap between the usable memory and ++ * the commpage where other things can be mapped. ++ * This sparseness gives us more flexibility to find ++ * an address range. ++ */ ++ goto naive; ++ } ++ return (unsigned long)-1; ++ } ++ munmap((void *)real_start, host_full_size); ++ if (real_start & ~qemu_host_page_mask) { ++ /* The same thing again, but with an extra qemu_host_page_size ++ * so that we can shift around alignment. ++ */ ++ unsigned long real_size = host_full_size + qemu_host_page_size; ++ real_start = (unsigned long) ++ mmap(NULL, real_size, PROT_NONE, flags, -1, 0); ++ if (real_start == (unsigned long)-1) { ++ if (host_size < host_full_size - qemu_host_page_size) { ++ goto naive; ++ } ++ return (unsigned long)-1; ++ } ++ munmap((void *)real_start, real_size); ++ real_start = HOST_PAGE_ALIGN(real_start); ++ } ++ current_start = real_start; ++ } ++ naive: ++#endif ++ + while (1) { + unsigned long real_start, real_size, aligned_size; + aligned_size = real_size = host_size; +-- +2.15.1 + |