Merge tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull more x86 updates from Borislav Petkov:

 - Remove a bunch of asm implementing condition flags testing in KVM's
   emulator in favor of int3_emulate_jcc() which is written in C

 - Replace KVM fastops with C-based stubs which avoids problems with the
   fastop infra related to latter not adhering to the C ABI due to their
   special calling convention and, more importantly, bypassing compiler
   control-flow integrity checking because they're written in asm

 - Remove wrongly used static branches and other ugliness accumulated
   over time in hyperv's hypercall implementation with a proper static
   function call to the correct hypervisor call variant

 - Add some fixes and modifications to allow running FRED-enabled
   kernels in KVM even on non-FRED hardware

 - Add kCFI improvements like validating indirect calls and prepare for
   enabling kCFI with GCC. Add cmdline params documentation and other
   code cleanups

 - Use the single-byte 0xd6 insn as the official #UD single-byte
   undefined opcode instruction as agreed upon by both x86 vendors

 - Other smaller cleanups and touchups all over the place

* tag 'x86_core_for_v6.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  x86,retpoline: Optimize patch_retpoline()
  x86,ibt: Use UDB instead of 0xEA
  x86/cfi: Remove __noinitretpoline and __noretpoline
  x86/cfi: Add "debug" option to "cfi=" bootparam
  x86/cfi: Standardize on common "CFI:" prefix for CFI reports
  x86/cfi: Document the "cfi=" bootparam options
  x86/traps: Clarify KCFI instruction layout
  compiler_types.h: Move __nocfi out of compiler-specific header
  objtool: Validate kCFI calls
  x86/fred: KVM: VMX: Always use FRED for IRQs when CONFIG_X86_FRED=y
  x86/fred: Play nice with invoking asm_fred_entry_from_kvm() on non-FRED hardware
  x86/fred: Install system vector handlers even if FRED isn't fully enabled
  x86/hyperv: Use direct call to hypercall-page
  x86/hyperv: Clean up hv_do_hypercall()
  KVM: x86: Remove fastops
  KVM: x86: Convert em_salc() to C
  KVM: x86: Introduce EM_ASM_3WCL
  KVM: x86: Introduce EM_ASM_1SRC2
  KVM: x86: Introduce EM_ASM_2CL
  KVM: x86: Introduce EM_ASM_2W
  ...

1 files changed, 5 insertions, 6 deletions

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 94519688b007..77e2d920a640 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -99,7 +99,7 @@ For 32-bit we have the following conventions - kernel is built with
 	.endif
 .endm
 
-.macro CLEAR_REGS clear_bp=1
+.macro CLEAR_REGS clear_callee=1
 	/*
 	 * Sanitize registers of values that a speculation attack might
 	 * otherwise want to exploit. The lower registers are likely clobbered
@@ -113,20 +113,19 @@ For 32-bit we have the following conventions - kernel is built with
 	xorl	%r9d,  %r9d	/* nospec r9  */
 	xorl	%r10d, %r10d	/* nospec r10 */
 	xorl	%r11d, %r11d	/* nospec r11 */
+	.if \clear_callee
 	xorl	%ebx,  %ebx	/* nospec rbx */
-	.if \clear_bp
 	xorl	%ebp,  %ebp	/* nospec rbp */
-	.endif
 	xorl	%r12d, %r12d	/* nospec r12 */
 	xorl	%r13d, %r13d	/* nospec r13 */
 	xorl	%r14d, %r14d	/* nospec r14 */
 	xorl	%r15d, %r15d	/* nospec r15 */
-
+	.endif
 .endm
 
-.macro PUSH_AND_CLEAR_REGS rdx=%rdx rcx=%rcx rax=%rax save_ret=0 clear_bp=1 unwind_hint=1
+.macro PUSH_AND_CLEAR_REGS rdx=%rdx rcx=%rcx rax=%rax save_ret=0 clear_callee=1 unwind_hint=1
 	PUSH_REGS rdx=\rdx, rcx=\rcx, rax=\rax, save_ret=\save_ret unwind_hint=\unwind_hint
-	CLEAR_REGS clear_bp=\clear_bp
+	CLEAR_REGS clear_callee=\clear_callee
 .endm
 
 .macro POP_REGS pop_rdi=1