From: Peter Zijlstra <peterz@infradead.org>
From: Peter Zijlstra <peterz@infradead.org>
To: David Woodhouse <dwmw2@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-kernel@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg KH <gregkh@linuxfoundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
Arjan Van De Ven <arjan.van.de.ven@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Jun Nakajima <jun.nakajima@intel.com>,
Asit Mallick <asit.k.mallick@intel.com>,
Jason Baron <jbaron@akamai.com>,
Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>
Subject: [PATCH 08/35] objtool: Implement jump_assert for _static_cpu_has()
Date: Thu, 18 Jan 2018 14:48:08 +0100 [thread overview]
Message-ID: <20180118140151.928378170@infradead.org> (raw)
In-Reply-To: 20180118134800.711245485@infradead.org
[-- Attachment #1: peterz-objtool-static_cpu_has.patch --]
[-- Type: text/plain, Size: 3885 bytes --]
Unlike the jump_label bits, static_cpu_has is implemented with
alternatives. We use the new type field to distinguish them from any
other alternatives
Like jump_labels, make static_cpu_has set static_jump_dest on the
instructions after the static branch such that we can assert on it.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
tools/objtool/check.c | 21 +++++++++++++++++++++
tools/objtool/special.c | 26 +++++++++++++++-----------
tools/objtool/special.h | 1 +
3 files changed, 37 insertions(+), 11 deletions(-)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -636,6 +636,12 @@ static int handle_group_alt(struct objto
fake_jump->ignore = true;
if (!special_alt->new_len) {
+ /*
+ * The NOP case for _static_cpu_has()
+ */
+ if (special_alt->static_cpu_has)
+ fake_jump->jump_dest->static_jump_dest = true;
+
*new_insn = fake_jump;
return 0;
}
@@ -664,6 +670,21 @@ static int handle_group_alt(struct objto
insn->sec, insn->offset);
return -1;
}
+
+ if (special_alt->static_cpu_has) {
+ if (insn->type != INSN_JUMP_UNCONDITIONAL) {
+ WARN_FUNC("not an unconditional jump in _static_cpu_has()",
+ insn->sec, insn->offset);
+ }
+ if (insn->jump_dest == fake_jump) {
+ WARN_FUNC("jump inside alternative for _static_cpu_has()",
+ insn->sec, insn->offset);
+ }
+ /*
+ * The JMP+disp case for _static_cpu_has()
+ */
+ insn->jump_dest->static_jump_dest = true;
+ }
}
if (!last_new_insn) {
--- a/tools/objtool/special.c
+++ b/tools/objtool/special.c
@@ -40,6 +40,10 @@
#define ALT_FEATURE_OFFSET 8
#define ALT_ORIG_LEN_OFFSET 10
#define ALT_NEW_LEN_OFFSET 11
+#define ALT_TYPE_OFFSET 13
+
+#define ALT_TYPE_DEFAULT 0
+#define ALT_TYPE_STATIC_CPU_HAS 1
#define X86_FEATURE_POPCNT (4*32+23)
@@ -48,7 +52,6 @@ struct special_entry {
bool group, jump_or_nop;
unsigned char size, orig, new;
unsigned char orig_len, new_len; /* group only */
- unsigned char feature; /* ALTERNATIVE macro CPU feature */
};
struct special_entry entries[] = {
@@ -60,7 +63,6 @@ struct special_entry entries[] = {
.orig_len = ALT_ORIG_LEN_OFFSET,
.new = ALT_NEW_OFFSET,
.new_len = ALT_NEW_LEN_OFFSET,
- .feature = ALT_FEATURE_OFFSET,
},
{
.sec = "__jump_table",
@@ -84,24 +86,23 @@ static int get_alt_entry(struct elf *elf
{
struct rela *orig_rela, *new_rela;
unsigned long offset;
+ void *data;
offset = idx * entry->size;
+ data = sec->data->d_buf + offset;
alt->group = entry->group;
alt->jump_or_nop = entry->jump_or_nop;
if (alt->group) {
- alt->orig_len = *(unsigned char *)(sec->data->d_buf + offset +
- entry->orig_len);
- alt->new_len = *(unsigned char *)(sec->data->d_buf + offset +
- entry->new_len);
- }
-
- if (entry->feature) {
unsigned short feature;
+ unsigned char type;
- feature = *(unsigned short *)(sec->data->d_buf + offset +
- entry->feature);
+ alt->orig_len = *(unsigned char *)(data + entry->orig_len);
+ alt->new_len = *(unsigned char *)(data + entry->new_len);
+
+ feature = *(unsigned short *)(data + ALT_FEATURE_OFFSET);
+ type = *(unsigned char *)(data + ALT_TYPE_OFFSET);
/*
* It has been requested that we don't validate the !POPCNT
@@ -110,6 +111,9 @@ static int get_alt_entry(struct elf *elf
*/
if (feature == X86_FEATURE_POPCNT)
alt->skip_orig = true;
+
+ if (type == ALT_TYPE_STATIC_CPU_HAS)
+ alt->static_cpu_has = true;
}
orig_rela = find_rela_by_dest(sec, offset + entry->orig);
--- a/tools/objtool/special.h
+++ b/tools/objtool/special.h
@@ -27,6 +27,7 @@ struct special_alt {
bool group;
bool skip_orig;
bool jump_or_nop;
+ bool static_cpu_has;
struct section *orig_sec;
unsigned long orig_off;
next prev parent reply other threads:[~2018-01-18 15:03 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-18 13:48 [PATCH 00/35] jump_label, objtool, IBRS and IBPB Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 01/35] jump_label: Add branch hints to static_branch_{un,}likely() Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 02/35] sched: Optimize ttwu_stat() Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 03/35] x86: Reindent _static_cpu_has Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 04/35] x86: Update _static_cpu_has to use all named variables Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 05/35] x86: Add a type field to alt_instr Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 06/35] objtool: Implement base jump_assert support Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 07/35] x86: Annotate static_cpu_has alternative Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` Peter Zijlstra, Peter Zijlstra [this message]
2018-01-18 13:48 ` [PATCH 09/35] objtool: Introduce special_type Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 10/35] x86/jump_label: Implement arch_static_assert() Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 11/35] objtool: Add retpoline validation Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 12/35] x86/paravirt: Annotate indirect calls Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 13/35] x86,nospec: Annotate indirect calls/jumps Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 14/35] x86: Annotate indirect jump in head_64.S Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 15/35] objtool: More complex static jump implementation Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 16/35] objtool: Use existing global variables for options Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 17/35] objtool: Even more complex static block checks Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 18/35] objtool: Another static block fail Peter Zijlstra, Peter Zijlstra
2018-01-19 16:42 ` Peter Zijlstra
2018-01-29 18:01 ` Josh Poimboeuf
2018-01-29 18:24 ` Peter Zijlstra
2018-01-18 13:48 ` [PATCH 19/35] objtool: Skip static assert when KCOV/KASAN Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 20/35] x86: Force asm-goto Peter Zijlstra, Peter Zijlstra
2018-01-18 16:25 ` David Woodhouse
2018-01-18 13:48 ` [PATCH 21/35] x86: Remove FAST_FEATURE_TESTS Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 22/35] x86/cpufeatures: Detect Speculation control feature Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 23/35] x86/speculation: Add basic speculation control code Peter Zijlstra, Peter Zijlstra
2018-01-18 16:37 ` Josh Poimboeuf
2018-01-18 17:08 ` Dave Hansen
2018-01-18 17:12 ` Paolo Bonzini
2018-01-18 18:24 ` Josh Poimboeuf
2018-01-18 19:08 ` Andrea Arcangeli
2018-01-18 23:25 ` Andy Lutomirski
2018-01-18 23:35 ` Andrew Cooper
2018-01-19 1:41 ` Andrea Arcangeli
2018-01-19 4:10 ` Andy Lutomirski
2018-01-19 4:15 ` Van De Ven, Arjan
2018-01-19 15:47 ` Andrea Arcangeli
2018-01-18 13:48 ` [PATCH 24/35] x86/msr: Move native_*msr macros out of microcode.h Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 25/35] x86/speculation: Add inlines to control Indirect Branch Speculation Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 26/35] x86/enter: Create macros to stop/restart " Peter Zijlstra, Peter Zijlstra
2018-01-18 19:44 ` Tim Chen
2018-01-18 13:48 ` [PATCH 27/35] x86/enter: Use IBRS on syscall and interrupts Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 28/35] x86/idle: Control Indirect Branch Speculation in idle Peter Zijlstra, Peter Zijlstra
2018-01-18 19:52 ` Andrew Cooper
2018-01-18 13:48 ` [PATCH 29/35] x86/speculation: Add IPBP support Peter Zijlstra, Peter Zijlstra
2018-01-18 16:22 ` Josh Poimboeuf
2018-01-18 18:31 ` Borislav Petkov
2018-01-18 18:35 ` Josh Poimboeuf
2018-01-18 18:46 ` Borislav Petkov
2018-01-18 13:48 ` [PATCH 30/35] x86/speculation: Use Indirect Branch Prediction Barrier in context switch Peter Zijlstra, Peter Zijlstra
2018-01-19 0:38 ` Tim Chen
2018-01-19 4:03 ` Kevin Easton
2018-01-19 20:26 ` Tim Chen
2018-01-18 13:48 ` [PATCH 31/35] x86/ibrs: Add new helper macros to save/restore MSR_IA32_SPEC_CTRL Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 32/35] x86/vmx: Direct access to MSR_IA32_SPEC_CTRL Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 33/35] x86/svm: " Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 34/35] x86/kvm: Add IBPB support Peter Zijlstra, Peter Zijlstra
2018-01-18 15:32 ` Paolo Bonzini
2018-01-19 15:25 ` Paolo Bonzini
2018-01-19 16:08 ` David Woodhouse
2018-01-19 16:27 ` Andy Lutomirski
2018-01-19 16:48 ` Paolo Bonzini
2018-01-18 13:48 ` [PATCH 35/35] x86/nospec: Add static assertions Peter Zijlstra, Peter Zijlstra
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