[gentoo-commits] proj/linux-patches:4.15 commit in: /

[Alice Ferrazzi]

commit:     f98193ddca07dc67810a96082be4e2a6d8026a66
Author:     Alice Ferrazzi <alicef <AT> gentoo <DOT> org>
AuthorDate: Mon Feb 26 14:17:39 2018 +0000
Commit:     Alice Ferrazzi <alicef <AT> gentoo <DOT> org>
CommitDate: Mon Feb 26 14:17:39 2018 +0000
URL:        https://gitweb.gentoo.org/proj/linux-patches.git/commit/?id=f98193dd

ia64 fix ptrace

 0000_README                |  6 +++-
 1700_ia64_fix_ptrace.patch | 87 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 92 insertions(+), 1 deletion(-)

diff --git a/0000_README b/0000_README
index af0f948..8e1b91f 100644
--- a/0000_README
+++ b/0000_README
@@ -75,6 +75,10 @@ Patch:  1510_fs-enable-link-security-restrictions-by-default.patch
 From:   http://sources.debian.net/src/linux/3.16.7-ckt4-3/debian/patches/debian/fs-enable-link-security-restrictions-by-default.patch/
 Desc:   Enable link security restrictions by default.
 
+Patch:  1700_ia64_fix_ptrace.patch 
+From:   https://patchwork.kernel.org/patch/10198159/
+Desc:   ia64: fix ptrace(PTRACE_GETREGS) (unbreaks strace, gdb).
+
 Patch:  2300_enable-poweroff-on-Mac-Pro-11.patch
 From:   http://kernel.ubuntu.com/git/ubuntu/ubuntu-xenial.git/patch/drivers/pci/quirks.c?id=5080ff61a438f3dd80b88b423e1a20791d8a774c
 Desc:   Workaround to enable poweroff on Mac Pro 11. See bug #601964.
@@ -93,7 +97,7 @@ Desc:   Ensure that /dev/root doesn't appear in /proc/mounts when bootint withou
 
 Patch:  2901_allocate_buffer_on_heap_rather_than_globally.patch
 From:   https://patchwork.kernel.org/patch/10194287/
-Desc:   Patchwork [v2] platform/x86: dell-laptop: Allocate buffer on heap rather than globally
+Desc:   Patchwork [v2] platform/x86: dell-laptop: Allocate buffer on heap rather than globally.
 
 Patch:  4200_fbcondecor.patch
 From:   http://www.mepiscommunity.org/fbcondecor

diff --git a/1700_ia64_fix_ptrace.patch b/1700_ia64_fix_ptrace.patch
new file mode 100644
index 0000000..6173b05
--- /dev/null
+++ b/1700_ia64_fix_ptrace.patch
@@ -0,0 +1,87 @@
+From patchwork Fri Feb  2 22:12:24 2018
+Content-Type: text/plain; charset="utf-8"
+MIME-Version: 1.0
+Content-Transfer-Encoding: 8bit
+Subject: ia64: fix ptrace(PTRACE_GETREGS) (unbreaks strace, gdb)
+From: Sergei Trofimovich <slyfox@g.o>
+X-Patchwork-Id: 10198159
+Message-Id: <20180202221224.16597-1-slyfox@g.o>
+To: Tony Luck <tony.luck@×××××.com>, Fenghua Yu <fenghua.yu@×××××.com>,
+ linux-ia64@×××××××××××.org, linux-kernel@×××××××××××.org
+Cc: Sergei Trofimovich <slyfox@g.o>
+Date: Fri,  2 Feb 2018 22:12:24 +0000
+
+The strace breakage looks like that:
+./strace: get_regs: get_regs_error: Input/output error
+
+It happens because ia64 needs to load unwind tables
+to read certain registers. Unwind tables fail to load
+due to GCC quirk on the following code:
+
+    extern char __end_unwind[];
+    const struct unw_table_entry *end = (struct unw_table_entry *)table_end;
+    table->end = segment_base + end[-1].end_offset;
+
+GCC does not generate correct code for this single memory
+reference after constant propagation (see https://gcc.gnu.org/PR84184).
+Two triggers are required for bad code generation:
+- '__end_unwind' has alignment lower (char), than
+  'struct unw_table_entry' (8).
+- symbol offset is negative.
+
+This commit workarounds it by fixing alignment of '__end_unwind'.
+While at it use hidden symbols to generate shorter gp-relative
+relocations.
+
+CC: Tony Luck <tony.luck@×××××.com>
+CC: Fenghua Yu <fenghua.yu@×××××.com>
+CC: linux-ia64@×××××××××××.org
+CC: linux-kernel@×××××××××××.org
+Bug: https://github.com/strace/strace/issues/33
+Bug: https://gcc.gnu.org/PR84184
+Reported-by: Émeric Maschino <emeric.maschino@×××××.com>
+Signed-off-by: Sergei Trofimovich <slyfox@g.o>
+Tested-by: stanton_arch@××××.com
+---
+ arch/ia64/include/asm/sections.h |  1 -
+ arch/ia64/kernel/unwind.c        | 15 ++++++++++++++-
+ 2 files changed, 14 insertions(+), 2 deletions(-)
+
+diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h
+index f3481408594e..0fc4f1757a44 100644
+--- a/arch/ia64/include/asm/sections.h
++++ b/arch/ia64/include/asm/sections.h
+@@ -24,7 +24,6 @@ extern char __start_gate_mckinley_e9_patchlist[], __end_gate_mckinley_e9_patchli
+ extern char __start_gate_vtop_patchlist[], __end_gate_vtop_patchlist[];
+ extern char __start_gate_fsyscall_patchlist[], __end_gate_fsyscall_patchlist[];
+ extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_bubble_down_patchlist[];
+-extern char __start_unwind[], __end_unwind[];
+ extern char __start_ivt_text[], __end_ivt_text[];
+ 
+ #undef dereference_function_descriptor
+diff --git a/arch/ia64/kernel/unwind.c b/arch/ia64/kernel/unwind.c
+index e04efa088902..025ba6700790 100644
+--- a/arch/ia64/kernel/unwind.c
++++ b/arch/ia64/kernel/unwind.c
+@@ -2243,7 +2243,20 @@ __initcall(create_gate_table);
+ void __init
+ unw_init (void)
+ {
+-	extern char __gp[];
++	#define __ia64_hidden __attribute__((visibility("hidden")))
++	/*
++	 * We use hidden symbols to generate more efficient code using
++	 * gp-relative addressing.
++	 */
++	extern char __gp[] __ia64_hidden;
++	/*
++	 * Unwind tables need to have proper alignment as init_unwind_table()
++	 * uses negative offsets against '__end_unwind'.
++	 * See https://gcc.gnu.org/PR84184
++	 */
++	extern const struct unw_table_entry __start_unwind[] __ia64_hidden;
++	extern const struct unw_table_entry __end_unwind[] __ia64_hidden;
++	#undef __ia64_hidden
+ 	extern void unw_hash_index_t_is_too_narrow (void);
+ 	long i, off;
+