4.4-stable review patch. If anyone has any objections, please let me know.
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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.u... [ backport to 4.4, hopefully correct, not tested... - gregkh ] Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/hv/hv.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
--- a/drivers/hv/hv.c +++ b/drivers/hv/hv.c @@ -31,6 +31,7 @@ #include <linux/clockchips.h> #include <asm/hyperv.h> #include <asm/mshyperv.h> +#include <asm/nospec-branch.h> #include "hyperv_vmbus.h"
/* The one and only */ @@ -103,9 +104,10 @@ static u64 do_hypercall(u64 control, voi return (u64)ULLONG_MAX;
__asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8"); - __asm__ __volatile__("call *%3" : "=a" (hv_status) : + __asm__ __volatile__(CALL_NOSPEC : + "=a" (hv_status) : "c" (control), "d" (input_address), - "m" (hypercall_page)); + THUNK_TARGET(hypercall_page));
return hv_status;
@@ -123,11 +125,12 @@ static u64 do_hypercall(u64 control, voi if (!hypercall_page) return (u64)ULLONG_MAX;
- __asm__ __volatile__ ("call *%8" : "=d"(hv_status_hi), + __asm__ __volatile__ (CALL_NOSPEC : "=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)); + "S"(output_address_lo), + THUNK_TARGET(hypercall_page));
return hv_status_lo | ((u64)hv_status_hi << 32); #endif /* !x86_64 */