From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: xen-devel@lists.xenproject.org, konrad@kernel.org,
julien.grall@arm.com, sstabellini@kernel.org,
ross.lagerwall@citrix.com
Cc: andrew.cooper3@citrix.com, Jan Beulich <jbeulich@suse.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: [PATCH v3 15/18] bug/x86/arm: Align bug_frames sections.
Date: Sun, 11 Sep 2016 16:35:22 -0400 [thread overview]
Message-ID: <1473626125-13683-16-git-send-email-konrad.wilk@oracle.com> (raw)
In-Reply-To: <1473626125-13683-1-git-send-email-konrad.wilk@oracle.com>
Most of the WARN_ON or BUG_ON sections are properly aligned on
x86. However on ARM and on x86 assembler the macros don't include
any aligment information - hence they end up being the default
byte granularity.
On ARM32 it is paramount that the aligment is word-size (4)
otherwise if one tries to use (uint32_t*) access (such
as livepatch ELF relocations) we get a Data Abort.
Enforcing bug_frames to have the proper aligment across all
architectures and in both C and x86 makes them all the same.
Furthermore on x86 the bloat-o-meter detects that with this
change:
[konrad@char xen]$ ~/linux/scripts/bloat-o-meter xen-syms xen-syms.align4
add/remove: 0/0 grow/shrink: 3/14 up/down: 115/-1497 (-1382)
function old new delta
mod_l1_entry 1490 1587 +97
p2m_switch_domain_altp2m_by_id 520 533 +13
p2m_switch_vcpu_altp2m_by_id 453 458 +5
machine_kexec 263 261 -2
hvm_do_IRQ_dpci 244 242 -2
sh_page_fault__guest_4 8252 8192 -60
sh_audit_gw 1529 1462 -67
validate_gl3e 337 264 -73
validate_gl4e 449 375 -74
p2m_altp2m_lazy_copy 730 652 -78
set_typed_p2m_entry 1346 1259 -87
virt_to_xen_l2e 491 365 -126
sh_x86_emulate_write__guest_4 443 288 -155
p2m_mem_access_check 1733 1576 -157
sh_x86_emulate_cmpxchg__guest_4 512 349 -163
__get_gfn_type_access 709 542 -167
map_pages_to_xen 4430 4144 -286
Total: Before=1974033, After=1972651, chg -0.07%
We end up making the binary file a bit smaller.
On ARM32:
add/remove: 1/0 grow/shrink: 0/1 up/down: 384/-288 (96)
function old new delta
gnttab_unpopulate_status_frames - 384 +384
do_grant_table_op 10808 10520 -288
And ARM64:
add/remove: 1/2 grow/shrink: 0/1 up/down: 4164/-4236 (-72)
function old new delta
gnttab_map_grant_ref - 4164 +4164
do_grant_table_op 9892 9836 -56
grant_map_exists 300 - -300
__gnttab_map_grant_ref 3880 - -3880
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
Cc: Julien Grall <julien.grall@arm.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
v3: First submission. Replaces the "livepatch/elf: Adjust section aligment to word"
patch.
---
xen/include/asm-arm/bug.h | 1 +
xen/include/asm-x86/bug.h | 1 +
2 files changed, 2 insertions(+)
diff --git a/xen/include/asm-arm/bug.h b/xen/include/asm-arm/bug.h
index 68353e1..773d63e 100644
--- a/xen/include/asm-arm/bug.h
+++ b/xen/include/asm-arm/bug.h
@@ -52,6 +52,7 @@ struct bug_frame {
".popsection\n" \
".pushsection .bug_frames." __stringify(type) ", \"a\", %progbits\n"\
"4:\n" \
+ ".align 4\n" \
".long (1b - 4b)\n" \
".long (2b - 4b)\n" \
".long (3b - 4b)\n" \
diff --git a/xen/include/asm-x86/bug.h b/xen/include/asm-x86/bug.h
index c5d2d4c..9bb4a19 100644
--- a/xen/include/asm-x86/bug.h
+++ b/xen/include/asm-x86/bug.h
@@ -98,6 +98,7 @@ extern const struct bug_frame __start_bug_frames[],
.popsection
.pushsection .bug_frames.\type, "a", @progbits
+ .p2align 2
.L\@bf:
.long (.L\@ud - .L\@bf) + \
((\line >> BUG_LINE_LO_WIDTH) << BUG_DISP_WIDTH)
--
2.4.11
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next prev parent reply other threads:[~2016-09-11 20:36 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-11 20:35 [PATCH v3] Livepatch for ARM 64 and 32 Konrad Rzeszutek Wilk
2016-09-11 20:35 ` [PATCH v3 01/18] arm/x86: Add HAS_[ALTERNATIVE|EX_TABLE] Konrad Rzeszutek Wilk
2016-09-12 15:28 ` Jan Beulich
2016-09-12 15:31 ` Julien Grall
2016-09-13 16:58 ` Konrad Rzeszutek Wilk
2016-09-11 20:35 ` [PATCH v3 02/18] livepatch: Reject payloads with .alternative or .ex_table if support is not built-in Konrad Rzeszutek Wilk
2016-09-16 12:50 ` Julien Grall
2016-09-11 20:35 ` [PATCH v3 03/18] arm/x86: change [modify, destroy]_xen_mappings to return error Konrad Rzeszutek Wilk
2016-09-16 13:06 ` Julien Grall
2016-09-11 20:35 ` [PATCH v3 04/18] arm/mm: Introduce modify_xen_mappings Konrad Rzeszutek Wilk
2016-09-11 20:35 ` [PATCH v3 05/18] arm: poison initmem when it is freed Konrad Rzeszutek Wilk
2016-09-16 13:31 ` Julien Grall
2016-09-11 20:35 ` [PATCH v3 06/18] livepatch: Initial ARM64 support Konrad Rzeszutek Wilk
2016-09-12 7:45 ` Jan Beulich
2016-09-11 20:35 ` [PATCH v3 07/18] livepatch: ARM/x86: Check displacement of old_addr and new_addr Konrad Rzeszutek Wilk
2016-09-12 15:36 ` Jan Beulich
2016-09-11 20:35 ` [PATCH v3 08/18] livepatch: ARM 32|64: Ignore mapping symbols: $[d, a, x] Konrad Rzeszutek Wilk
2016-09-12 15:52 ` Jan Beulich
2016-09-11 20:35 ` [PATCH v3 09/18] livepatch/arm/x86: Check payload for for unwelcomed symbols Konrad Rzeszutek Wilk
2016-09-12 15:55 ` Jan Beulich
2016-09-11 20:35 ` [PATCH v3 10/18] livepatch: Move test-cases to their own sub-directory in test Konrad Rzeszutek Wilk
2016-09-11 20:35 ` [PATCH v3 11/18] livepatch: tests: Move the .name value to .rodata Konrad Rzeszutek Wilk
2016-09-11 20:35 ` [PATCH v3 12/18] livepatch: tests: Make them compile under ARM64 Konrad Rzeszutek Wilk
2016-09-11 20:35 ` [PATCH v3 13/18] livepatch: x86, ARM, alternative: Expose FEATURE_LIVEPATCH Konrad Rzeszutek Wilk
2016-09-13 9:14 ` Jan Beulich
2016-09-11 20:35 ` [PATCH v3 14/18] xen/arm32: Add an helper to invalidate all instruction caches Konrad Rzeszutek Wilk
2016-09-11 20:35 ` Konrad Rzeszutek Wilk [this message]
2016-09-13 9:21 ` [PATCH v3 15/18] bug/x86/arm: Align bug_frames sections Jan Beulich
2016-09-13 19:26 ` Konrad Rzeszutek Wilk
2016-09-11 20:35 ` [PATCH v3 16/18] livepatch: ARM32 support Konrad Rzeszutek Wilk
2016-09-12 7:48 ` Jan Beulich
2016-09-11 20:35 ` [PATCH v3 17/18] livepatch, arm[32|64]: Share arch_livepatch_revert_jmp Konrad Rzeszutek Wilk
2016-09-11 20:35 ` [PATCH v3 18/18] livepatch: arm[32, 64], x86: NOP test-case Konrad Rzeszutek Wilk
2016-09-16 13:35 ` [PATCH v3] Livepatch for ARM 64 and 32 Julien Grall
2016-09-16 13:41 ` Konrad Rzeszutek Wilk
2016-09-16 13:45 ` Julien Grall
2016-09-16 14:35 ` Konrad Rzeszutek Wilk
2016-09-16 14:43 ` Julien Grall
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