lkml.org 
[lkml]   [2018]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Date
Subject[PATCH 3.16 28/76] x86/retpoline/hyperv: Convert assembler indirect jumps
3.16.56-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: David Woodhouse <dwmw@amazon.co.uk>

commit e70e5892b28c18f517f29ab6e83bd57705104b31 upstream.

Convert all indirect jumps in hyperv inline asm code to use non-speculative
sequences when CONFIG_RETPOLINE is enabled.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: thomas.lendacky@amd.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kees Cook <keescook@google.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Link: https://lkml.kernel.org/r/1515707194-20531-9-git-send-email-dwmw@amazon.co.uk
[bwh: Backported to 3.16:
- Drop changes to hv_do_fast_hypercall8()
- Include earlier updates to the asm constraints
- Adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/hv/hv.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -29,6 +29,7 @@
#include <linux/version.h>
#include <linux/interrupt.h>
#include <asm/hyperv.h>
+#include <asm/nospec-branch.h>
#include "hyperv_vmbus.h"

/* The one and only */
@@ -93,10 +94,13 @@ static u64 do_hypercall(u64 control, voi
u64 output_address = (output) ? virt_to_phys(output) : 0;
void *hypercall_page = hv_context.hypercall_page;

- __asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8");
- __asm__ __volatile__("call *%3" : "=a" (hv_status) :
- "c" (control), "d" (input_address),
- "m" (hypercall_page));
+ __asm__ __volatile__("mov %4, %%r8\n"
+ CALL_NOSPEC
+ : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+ "+c" (control), "+d" (input_address)
+ : "r" (output_address),
+ THUNK_TARGET(hypercall_page)
+ : "cc", "memory", "r8", "r9", "r10", "r11");

return hv_status;

@@ -114,11 +118,14 @@ static u64 do_hypercall(u64 control, voi
u32 output_address_lo = output_address & 0xFFFFFFFF;
void *hypercall_page = hv_context.hypercall_page;

- __asm__ __volatile__ ("call *%8" : "=d"(hv_status_hi),
- "=a"(hv_status_lo) : "d" (control_hi),
- "a" (control_lo), "b" (input_address_hi),
- "c" (input_address_lo), "D"(output_address_hi),
- "S"(output_address_lo), "m" (hypercall_page));
+ __asm__ __volatile__(CALL_NOSPEC
+ : "=d" (hv_status_hi), "=a" (hv_status_lo),
+ "+c" (input_address_lo), ASM_CALL_CONSTRAINT
+ : "d" (control_hi), "a" (control_lo),
+ "b" (input_address_hi),
+ "D"(output_address_hi), "S"(output_address_lo),
+ THUNK_TARGET(hypercall_page)
+ : "cc", "memory");

return hv_status_lo | ((u64)hv_status_hi << 32);
#endif /* !x86_64 */
\
 
 \ /
  Last update: 2018-03-12 04:36    [W:0.334 / U:1.592 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site