riscv: use local label names instead of global ones in assembly

[ Upstream commit 5cd900b ]

Local labels should be prefix by '.L' or they'll be exported in the
symbol table. Additionally, this messes up the backtrace by displaying
an incorrect symbol:

  ...
  [   12.751810] [<ffffffff80441628>] _copy_from_user+0x28/0xc2
  [   12.752035] [<ffffffff800152ca>] handle_misaligned_load+0x1ca/0x2fc
  [   12.752310] [<ffffffff80a033e8>] do_trap_load_misaligned+0x24/0xee
  [   12.752596] [<ffffffff80a0dcae>] _new_vmalloc_restore_context_a0+0xc2/0xce

After:
  ...
  [   10.243916] [<ffffffff804415e4>] _copy_from_user+0x28/0xc2
  [   10.244026] [<ffffffff800152ca>] handle_misaligned_load+0x1ca/0x2fc
  [   10.244150] [<ffffffff80a033a0>] do_trap_load_misaligned+0x24/0xee
  [   10.244268] [<ffffffff80a0dc66>] handle_exception+0x146/0x152

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Fixes: 503638e ("riscv: Stop emitting preventive sfence.vma for new vmalloc mappings")
Link: https://lore.kernel.org/r/20250103141814.508865-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

arch/riscv/kernel/entry.S

@@ -23,21 +23,21 @@
 	REG_S 	a0, TASK_TI_A0(tp)
 	csrr 	a0, CSR_CAUSE
 	/* Exclude IRQs */
-	blt  	a0, zero, _new_vmalloc_restore_context_a0
+	blt  	a0, zero, .Lnew_vmalloc_restore_context_a0
 
 	REG_S 	a1, TASK_TI_A1(tp)
 	/* Only check new_vmalloc if we are in page/protection fault */
 	li   	a1, EXC_LOAD_PAGE_FAULT
-	beq  	a0, a1, _new_vmalloc_kernel_address
+	beq  	a0, a1, .Lnew_vmalloc_kernel_address
 	li   	a1, EXC_STORE_PAGE_FAULT
-	beq  	a0, a1, _new_vmalloc_kernel_address
+	beq  	a0, a1, .Lnew_vmalloc_kernel_address
 	li   	a1, EXC_INST_PAGE_FAULT
-	bne  	a0, a1, _new_vmalloc_restore_context_a1
+	bne  	a0, a1, .Lnew_vmalloc_restore_context_a1
 
-_new_vmalloc_kernel_address:
+.Lnew_vmalloc_kernel_address:
 	/* Is it a kernel address? */
 	csrr 	a0, CSR_TVAL
-	bge 	a0, zero, _new_vmalloc_restore_context_a1
+	bge 	a0, zero, .Lnew_vmalloc_restore_context_a1
 
 	/* Check if a new vmalloc mapping appeared that could explain the trap */
 	REG_S	a2, TASK_TI_A2(tp)
@@ -69,7 +69,7 @@ _new_vmalloc_kernel_address:
 	/* Check the value of new_vmalloc for this cpu */
 	REG_L	a2, 0(a0)
 	and	a2, a2, a1
-	beq	a2, zero, _new_vmalloc_restore_context
+	beq	a2, zero, .Lnew_vmalloc_restore_context
 
 	/* Atomically reset the current cpu bit in new_vmalloc */
 	amoxor.d	a0, a1, (a0)
@@ -83,11 +83,11 @@ _new_vmalloc_kernel_address:
 	csrw	CSR_SCRATCH, x0
 	sret
 
-_new_vmalloc_restore_context:
+.Lnew_vmalloc_restore_context:
 	REG_L 	a2, TASK_TI_A2(tp)
-_new_vmalloc_restore_context_a1:
+.Lnew_vmalloc_restore_context_a1:
 	REG_L 	a1, TASK_TI_A1(tp)
-_new_vmalloc_restore_context_a0:
+.Lnew_vmalloc_restore_context_a0:
 	REG_L	a0, TASK_TI_A0(tp)
 .endm