arm64: remove processor_id

The global processor_id is assigned the MIDR_EL1 value of the boot
CPU in the early init code, but is never referenced afterwards.

As the relevance of the MIDR_EL1 value of the boot CPU is debatable
anyway, especially under big.LITTLE, let's remove it before anyone
starts using it.

Tested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

2 files changed, 1 insertions, 9 deletions

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index ebb9e630230a..88f14a77eac0 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -244,7 +244,6 @@ ENTRY(stext)
         bl      el2_setup                       // Drop to EL1, w20=cpu_boot_mode
         bl      __calc_phys_offset              // x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET
         bl      set_cpu_boot_mode_flag
-        mrs     x22, midr_el1                   // x22=cpuid
 
         bl      __vet_fdt
         bl      __create_page_tables            // x25=TTBR0, x26=TTBR1
@@ -427,7 +426,6 @@ __switch_data:
         .quad   __mmap_switched
         .quad   __bss_start                     // x6
         .quad   __bss_stop                      // x7
-        .quad   processor_id                    // x4
         .quad   __fdt_pointer                   // x5
         .quad   memstart_addr                   // x6
         .quad   init_thread_union + THREAD_START_SP // sp
@@ -445,11 +443,10 @@ __mmap_switched:
         str     xzr, [x6], #8                   // Clear BSS
         b       1b
 2:
-        ldp     x4, x5, [x3], #16
+        ldr     x5, [x3], #8
         ldr     x6, [x3], #8
         ldr     x16, [x3]
         mov     sp, x16
-        str     x22, [x4]                       // Save processor ID
         str     x21, [x5]                       // Save FDT pointer
         str     x24, [x6]                       // Save PHYS_OFFSET
         mov     x29, #0
@@ -621,8 +618,6 @@ ENTRY(secondary_startup)
         /*
          * Common entry point for secondary CPUs.
          */
-        mrs     x22, midr_el1                   // x22=cpuid
-
         pgtbl   x25, x26, x28                   // x25=TTBR0, x26=TTBR1
         bl      __cpu_setup                     // initialise processor
 
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 3852405d70b5..1783b38cf4c0 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -63,9 +63,6 @@
 #include <asm/efi.h>
 #include <asm/virt.h>
 
-unsigned int processor_id;
-EXPORT_SYMBOL(processor_id);
-
 unsigned long elf_hwcap __read_mostly;
 EXPORT_SYMBOL_GPL(elf_hwcap);