Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus

* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: (36 commits)
  MIPS: Calculate proper ebase value for 64-bit kernels
  MIPS: Alchemy: DB1200: Remove custom wait implementation
  MIPS: Big Sur: Make defconfig more useful.
  MIPS: Fix __vmalloc() etc. on MIPS for non-GPL modules
  MIPS: Sibyte: Fix M3 TLB exception handler workaround.
  MIPS: BCM63xx: Fix build failure in board_bcm963xx.c
  MIPS: uasm: Add OR instruction.
  MIPS: Sibyte: Apply M3 workaround only on affected chip types and versions.
  MIPS: BCM63xx: Initialize gpio_out_low & out_high to current value at boot.
  MIPS: BCM63xx: Register SSB SPROM fallback in board's first stage callback
  MIPS: BCM63xx: Fix typo in cpu-feature-overrides file.
  MIPS: BCM63xx: Add support for second uart.
  MIPS: BCM63xx: Fix double gpio registration.
  MIPS: BCM63xx: Add DWVS0 board
  MIPS: BCM63xx: Add the RTA1025W-16 BCM6348-based board to suppported boards.
  MIPS: BCM63xx: Fix BCM6338 and BCM6345 gpio count
  MIPS: libgcc.h: Checkpatch cleanup
  MIPS: Loongson-2F: Flush the branch target history in BTB and RAS
  MIPS: Move signal trampolines off of the stack.
  MIPS: Preliminary VDSO
  ...

1 files changed, 19 insertions, 0 deletions

diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h
index 3b6da3330e32..c8419129e770 100644
--- a/arch/mips/include/asm/stackframe.h
+++ b/arch/mips/include/asm/stackframe.h
@@ -121,6 +121,25 @@
                 .endm
 #else
                 .macro  get_saved_sp    /* Uniprocessor variation */
+#ifdef CONFIG_CPU_LOONGSON2F
+                /*
+                 * Clear BTB (branch target buffer), forbid RAS (return address
+                 * stack) to workaround the Out-of-order Issue in Loongson2F
+                 * via its diagnostic register.
+                 */
+                move    k0, ra
+                jal     1f
+                 nop
+1:              jal     1f
+                 nop
+1:              jal     1f
+                 nop
+1:              jal     1f
+                 nop
+1:              move    ra, k0
+                li      k0, 3
+                mtc0    k0, $22
+#endif /* CONFIG_CPU_LOONGSON2F */
 #if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32)
                 lui     k1, %hi(kernelsp)
 #else