From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Fenghua Yu <fenghua.yu@intel.com>,
Tony Luck <tony.luck@intel.com>,
Yu-cheng Yu <yu-cheng.yu@intel.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Borislav Petkov <bp@suse.de>,
Peter Zijlstra <peterz@infradead.org>,
Kan Liang <kan.liang@linux.intel.com>,
"Chang Seok Bae" <chang.seok.bae@intel.com>,
Megha Dey <megha.dey@linux.intel.com>,
Oliver Sang <oliver.sang@intel.com>
Subject: [patch V4 52/65] x86/fpu: Hook up PKRU into ptrace()
Date: Wed, 23 Jun 2021 14:02:19 +0200 [thread overview]
Message-ID: <20210623121456.508770763@linutronix.de> (raw)
In-Reply-To: 20210623120127.327154589@linutronix.de
From: Dave Hansen <dave.hansen@linux.intel.com>
One nice thing about having PKRU be XSAVE-managed is that it gets naturally
exposed into the XSAVE-using ABIs. Now that XSAVE will not be used to
manage PKRU, these ABIs need to be manually enabled to deal with PKRU.
ptrace() uses copy_uabi_xstate_to_kernel() to collect the tracee's
XSTATE. As PKRU is not in the task's XSTATE buffer, use task->thread.pkru
for filling in up the ptrace buffer.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
---
arch/x86/include/asm/fpu/xstate.h | 2 +-
arch/x86/kernel/fpu/regset.c | 10 ++++------
arch/x86/kernel/fpu/xstate.c | 25 ++++++++++++++++++-------
3 files changed, 23 insertions(+), 14 deletions(-)
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -139,7 +139,7 @@ enum xstate_copy_mode {
};
struct membuf;
-void copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
+void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk,
enum xstate_copy_mode mode);
#endif
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -78,7 +78,7 @@ int xfpregs_get(struct task_struct *targ
sizeof(fpu->state.fxsave));
}
- copy_xstate_to_uabi_buf(to, &fpu->state.xsave, XSTATE_COPY_FX);
+ copy_xstate_to_uabi_buf(to, target, XSTATE_COPY_FX);
return 0;
}
@@ -127,14 +127,12 @@ int xfpregs_set(struct task_struct *targ
int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
struct membuf to)
{
- struct fpu *fpu = &target->thread.fpu;
-
if (!cpu_feature_enabled(X86_FEATURE_XSAVE))
return -ENODEV;
- sync_fpstate(fpu);
+ sync_fpstate(&target->thread.fpu);
- copy_xstate_to_uabi_buf(to, &fpu->state.xsave, XSTATE_COPY_XSAVE);
+ copy_xstate_to_uabi_buf(to, target, XSTATE_COPY_XSAVE);
return 0;
}
@@ -337,7 +335,7 @@ int fpregs_get(struct task_struct *targe
struct membuf mb = { .p = &fxsave, .left = sizeof(fxsave) };
/* Handle init state optimized xstate correctly */
- copy_xstate_to_uabi_buf(mb, &fpu->state.xsave, XSTATE_COPY_FP);
+ copy_xstate_to_uabi_buf(mb, target, XSTATE_COPY_FP);
fx = &fxsave;
} else {
fx = &fpu->state.fxsave;
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -962,7 +962,7 @@ static void copy_feature(bool from_xstat
/**
* copy_xstate_to_uabi_buf - Copy kernel saved xstate to a UABI buffer
* @to: membuf descriptor
- * @xsave: The kernel xstate buffer to copy from
+ * @tsk: The task from which to copy the saved xstate
* @copy_mode: The requested copy mode
*
* Converts from kernel XSAVE or XSAVES compacted format to UABI conforming
@@ -971,10 +971,11 @@ static void copy_feature(bool from_xstat
*
* It supports partial copy but @to.pos always starts from zero.
*/
-void copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsave,
+void copy_xstate_to_uabi_buf(struct membuf to, struct task_struct *tsk,
enum xstate_copy_mode copy_mode)
{
const unsigned int off_mxcsr = offsetof(struct fxregs_state, mxcsr);
+ struct xregs_state *xsave = &tsk->thread.fpu.state.xsave;
struct xregs_state *xinit = &init_fpstate.xsave;
struct xstate_header header;
unsigned int zerofrom;
@@ -1048,11 +1049,21 @@ void copy_xstate_to_uabi_buf(struct memb
if (zerofrom < xstate_offsets[i])
membuf_zero(&to, xstate_offsets[i] - zerofrom);
- copy_feature(header.xfeatures & BIT_ULL(i), &to,
- __raw_xsave_addr(xsave, i),
- __raw_xsave_addr(xinit, i),
- xstate_sizes[i]);
-
+ if (i == XFEATURE_PKRU) {
+ struct pkru_state pkru = {0};
+ /*
+ * PKRU is not necessarily up to date in the
+ * thread's XSAVE buffer. Fill this part from the
+ * per-thread storage.
+ */
+ pkru.pkru = tsk->thread.pkru;
+ membuf_write(&to, &pkru, sizeof(pkru));
+ } else {
+ copy_feature(header.xfeatures & BIT_ULL(i), &to,
+ __raw_xsave_addr(xsave, i),
+ __raw_xsave_addr(xinit, i),
+ xstate_sizes[i]);
+ }
/*
* Keep track of the last copied state in the non-compacted
* target buffer for gap zeroing.
next prev parent reply other threads:[~2021-06-23 12:25 UTC|newest]
Thread overview: 142+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 12:01 [patch V4 00/65] x86/fpu: Spring cleaning and PKRU sanitizing Thomas Gleixner
2021-06-23 12:01 ` [patch V4 01/65] x86/fpu: Fix copy_xstate_to_kernel() gap handling Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 02/65] x86/pkeys: Revert a5eff7259790 ("x86/pkeys: Add PKRU value to init_fpstate") Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 03/65] x86/fpu: Mark various FPU states __ro_after_init Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] x86/fpu: Mark various FPU state variables __ro_after_init tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 04/65] x86/fpu: Make xfeatures_mask_all __ro_after_init Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 05/65] x86/fpu: Get rid of fpu__get_supported_xfeatures_mask() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 06/65] x86/fpu: Remove unused get_xsave_field_ptr() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 07/65] x86/fpu: Move inlines where they belong Thomas Gleixner
2021-06-23 18:43 ` Bae, Chang Seok
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 08/65] x86/fpu: Limit xstate copy size in xstateregs_set() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 09/65] x86/fpu: Sanitize xstateregs_set() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2022-07-14 4:04 ` [patch V4 09/65] " Andrei Vagin
2022-07-25 17:47 ` Dave Hansen
2022-07-25 17:57 ` Andrei Vagin
2022-07-25 21:26 ` Dave Hansen
2022-07-28 23:32 ` Chang S. Bae
2022-08-05 12:12 ` Andrei Vagin
2022-08-05 18:24 ` Chang S. Bae
2022-08-05 18:35 ` Dave Hansen
2021-06-23 12:01 ` [patch V4 10/65] x86/fpu: Reject invalid MXCSR values in copy_kernel_to_xstate() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 11/65] x86/fpu: Simplify PTRACE_GETREGS code Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Dave Hansen
2021-06-23 12:01 ` [patch V4 12/65] x86/fpu: Rewrite xfpregs_set() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Andy Lutomirski
2021-06-23 12:01 ` [patch V4 13/65] x86/fpu: Fail ptrace() requests that try to set invalid MXCSR values Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Andy Lutomirski
2021-06-23 12:01 ` [patch V4 14/65] x86/fpu: Clean up fpregs_set() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Andy Lutomirski
2021-06-23 12:01 ` [patch V4 15/65] x86/fpu: Make copy_xstate_to_kernel() usable for [x]fpregs_get() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-24 15:09 ` [PATCH] x86/fpu/xstate: Clear xstate header in copy_xstate_to_uabi_buf() again Thomas Gleixner
2021-06-24 15:41 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 16/65] x86/fpu: Use copy_xstate_to_uabi_buf() in xfpregs_get() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 17/65] x86/fpu: Use copy_xstate_to_uabi_buf() in fpregs_get() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 18/65] x86/fpu: Remove fpstate_sanitize_xstate() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 19/65] x86/fpu/regset: Move fpu__read_begin() into regset Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 20/65] x86/fpu: Move fpu__write_begin() to regset Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 21/65] x86/fpu: Get rid of using_compacted_format() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 22/65] x86/kvm: Avoid looking up PKRU in XSAVE buffer Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Dave Hansen
2021-06-23 12:01 ` [patch V4 23/65] x86/fpu: Cleanup arch_set_user_pkey_access() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 24/65] x86/fpu: Get rid of copy_supervisor_to_kernel() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 25/65] x86/fpu: Rename copy_xregs_to_kernel() and copy_kernel_to_xregs() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 26/65] x86/fpu: Rename copy_user_to_xregs() and copy_xregs_to_user() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 27/65] x86/fpu: Rename fxregs related copy functions Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] x86/fpu: Rename fxregs-related " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 28/65] x86/math-emu: Rename frstor() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 29/65] x86/fpu: Rename fregs related copy functions Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] x86/fpu: Rename fregs-related " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 30/65] x86/fpu: Rename xstate copy functions which are related to UABI Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 31/65] x86/fpu: Deduplicate copy_uabi_from_user/kernel_to_xstate() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:01 ` [patch V4 32/65] x86/fpu: Rename copy_fpregs_to_fpstate() to save_fpregs_to_fpstate() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 33/65] x86/fpu: Get rid of the FNSAVE optimization Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 34/65] x86/fpu: Rename copy_kernel_to_fpregs() to restore_fpregs_from_fpstate() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 35/65] x86/fpu: Rename initstate copy functions Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 36/65] x86/fpu: Rename "dynamic" XSTATEs to "independent" Thomas Gleixner
2021-06-23 12:02 ` [patch V4 37/65] x86/fpu/xstate: Sanitize handling of independent features Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 38/65] x86/pkeys: Move read_pkru() and write_pkru() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Dave Hansen
2021-06-23 12:02 ` [patch V4 39/65] x86/fpu: Rename and sanitize fpu__save/copy() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 40/65] x86/cpu: Sanitize X86_FEATURE_OSPKE Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 41/65] x86/pkru: Provide pkru_get_init_value() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 42/65] x86/pkru: Provide pkru_write_default() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 43/65] x86/cpu: Write the default PKRU value when enabling PKE Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 44/65] x86/fpu: Use pkru_write_default() in copy_init_fpstate_to_fpregs() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 45/65] x86/fpu: Rename fpu__clear_all() to fpu_flush_thread() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 46/65] x86/fpu: Clean up the fpu__clear() variants Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Andy Lutomirski
2021-06-23 12:02 ` [patch V4 47/65] x86/fpu: Rename __fpregs_load_activate() to fpregs_restore_userregs() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 48/65] x86/fpu: Move FXSAVE_LEAK quirk info __copy_kernel_to_fpregs() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 49/65] x86/fpu: Rename xfeatures_mask_user() to xfeatures_mask_uabi() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 50/65] x86/fpu: Dont restore PKRU in fpregs_restore_userspace() Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 51/65] x86/fpu: Add PKRU storage outside of task XSAVE buffer Thomas Gleixner
2021-06-23 22:09 ` [tip: x86/fpu] " tip-bot2 for Dave Hansen
2021-06-23 12:02 ` Thomas Gleixner [this message]
2021-06-23 22:08 ` [tip: x86/fpu] x86/fpu: Hook up PKRU into ptrace() tip-bot2 for Dave Hansen
2021-06-23 12:02 ` [patch V4 53/65] x86/fpu: Mask PKRU from kernel XRSTOR[S] operations Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 54/65] x86/fpu: Remove PKRU handling from switch_fpu_finish() Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 55/65] x86/fpu: Dont store PKRU in xstate in fpu_reset_fpstate() Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] x86/fpu: Don't " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 56/65] x86/pkru: Remove xstate fiddling from write_pkru() Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 57/65] x86/fpu: Mark init_fpstate __ro_after_init Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 58/65] x86/fpu/signal: Move initial checks into fpu__sig_restore() Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] x86/fpu/signal: Move initial checks into fpu__restore_sig() tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 59/65] x86/fpu/signal: Remove the legacy alignment check Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 60/65] x86/fpu/signal: Sanitize the xstate check on sigframe Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 61/65] x86/fpu/signal: Sanitize copy_user_to_fpregs_zeroing() Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 62/65] x86/fpu/signal: Split out the direct restore code Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 63/65] x86/fpu: Return proper error codes from user access functions Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 64/65] x86/fpu/signal: Handle #PF in the direct restore path Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-23 12:02 ` [patch V4 65/65] x86/fpu/signal: Let xrstor handle the features to init Thomas Gleixner
2021-06-23 22:08 ` [tip: x86/fpu] " tip-bot2 for Thomas Gleixner
2021-06-25 14:50 ` [patch V4 00/65] x86/fpu: Spring cleaning and PKRU sanitizing Oliver Sang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210623121456.508770763@linutronix.de \
--to=tglx@linutronix.de \
--cc=bigeasy@linutronix.de \
--cc=bp@suse.de \
--cc=chang.seok.bae@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=fenghua.yu@intel.com \
--cc=kan.liang@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=megha.dey@linux.intel.com \
--cc=oliver.sang@intel.com \
--cc=peterz@infradead.org \
--cc=tony.luck@intel.com \
--cc=yu-cheng.yu@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).