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Subject[PATCH V5 48/50] x86/entry: Remove the unused ASM macros
Date
From: Lai Jiangshan <laijs@linux.alibaba.com>

They are implemented and used in C code. The ASM version is not needed
any more.

FENCE_SWAPGS_USER_ENTRY is not removed because it is still being used
in the nmi userspace path. It could be possible to be removed in
future entry code enhancement.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
arch/x86/entry/calling.h | 99 ----------------------------------------
1 file changed, 99 deletions(-)

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 9065c31d2875..d42012fc694d 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -210,53 +210,6 @@ For 32-bit we have the following conventions - kernel is built with
popq %rax
.endm

-.macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req
- ALTERNATIVE "jmp .Ldone_\@", "", X86_FEATURE_PTI
- movq %cr3, \scratch_reg
- movq \scratch_reg, \save_reg
- /*
- * Test the user pagetable bit. If set, then the user page tables
- * are active. If clear CR3 already has the kernel page table
- * active.
- */
- bt $PTI_USER_PGTABLE_BIT, \scratch_reg
- jnc .Ldone_\@
-
- ADJUST_KERNEL_CR3 \scratch_reg
- movq \scratch_reg, %cr3
-
-.Ldone_\@:
-.endm
-
-.macro RESTORE_CR3 scratch_reg:req save_reg:req
- ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI
-
- /* No need to restore when the saved CR3 is kernel CR3. */
- bt $PTI_USER_PGTABLE_BIT, \save_reg
- jnc .Lend_\@
-
- ALTERNATIVE "jmp .Lwrcr3_\@", "", X86_FEATURE_PCID
-
- /*
- * Check if there's a pending flush for the user ASID we're
- * about to set.
- */
- movq \save_reg, \scratch_reg
- andq $(0x7FF), \scratch_reg
- bt \scratch_reg, THIS_CPU_user_pcid_flush_mask
- jnc .Lnoflush_\@
-
- btr \scratch_reg, THIS_CPU_user_pcid_flush_mask
- jmp .Lwrcr3_\@
-
-.Lnoflush_\@:
- SET_NOFLUSH_BIT \save_reg
-
-.Lwrcr3_\@:
- movq \save_reg, %cr3
-.Lend_\@:
-.endm
-
#else /* CONFIG_PAGE_TABLE_ISOLATION=n: */

.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req
@@ -265,10 +218,6 @@ For 32-bit we have the following conventions - kernel is built with
.endm
.macro SWITCH_TO_USER_CR3_STACK scratch_reg:req
.endm
-.macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req
-.endm
-.macro RESTORE_CR3 scratch_reg:req save_reg:req
-.endm

#endif

@@ -277,17 +226,10 @@ For 32-bit we have the following conventions - kernel is built with
*
* FENCE_SWAPGS_USER_ENTRY is used in the user entry swapgs code path, to
* prevent a speculative swapgs when coming from kernel space.
- *
- * FENCE_SWAPGS_KERNEL_ENTRY is used in the kernel entry non-swapgs code path,
- * to prevent the swapgs from getting speculatively skipped when coming from
- * user space.
*/
.macro FENCE_SWAPGS_USER_ENTRY
ALTERNATIVE "", "lfence", X86_FEATURE_FENCE_SWAPGS_USER
.endm
-.macro FENCE_SWAPGS_KERNEL_ENTRY
- ALTERNATIVE "", "lfence", X86_FEATURE_FENCE_SWAPGS_KERNEL
-.endm

.macro STACKLEAK_ERASE_NOCLOBBER
#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
@@ -297,12 +239,6 @@ For 32-bit we have the following conventions - kernel is built with
#endif
.endm

-.macro SAVE_AND_SET_GSBASE scratch_reg:req save_reg:req
- rdgsbase \save_reg
- GET_PERCPU_BASE \scratch_reg
- wrgsbase \scratch_reg
-.endm
-
#else /* CONFIG_X86_64 */
# undef UNWIND_HINT_IRET_REGS
# define UNWIND_HINT_IRET_REGS
@@ -313,38 +249,3 @@ For 32-bit we have the following conventions - kernel is built with
call stackleak_erase
#endif
.endm
-
-#ifdef CONFIG_SMP
-
-/*
- * CPU/node NR is loaded from the limit (size) field of a special segment
- * descriptor entry in GDT.
- */
-.macro LOAD_CPU_AND_NODE_SEG_LIMIT reg:req
- movq $__CPUNODE_SEG, \reg
- lsl \reg, \reg
-.endm
-
-/*
- * Fetch the per-CPU GSBASE value for this processor and put it in @reg.
- * We normally use %gs for accessing per-CPU data, but we are setting up
- * %gs here and obviously can not use %gs itself to access per-CPU data.
- *
- * Do not use RDPID, because KVM loads guest's TSC_AUX on vm-entry and
- * may not restore the host's value until the CPU returns to userspace.
- * Thus the kernel would consume a guest's TSC_AUX if an NMI arrives
- * while running KVM's run loop.
- */
-.macro GET_PERCPU_BASE reg:req
- LOAD_CPU_AND_NODE_SEG_LIMIT \reg
- andq $VDSO_CPUNODE_MASK, \reg
- movq __per_cpu_offset(, \reg, 8), \reg
-.endm
-
-#else
-
-.macro GET_PERCPU_BASE reg:req
- movq pcpu_unit_offsets(%rip), \reg
-.endm
-
-#endif /* CONFIG_SMP */
--
2.19.1.6.gb485710b
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