File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/sparc/kernel/rtrap_32.S b/arch/sparc/kernel/rtrap_32.S
new file mode 100644
index 0000000..6c34de0
--- /dev/null
+++ b/arch/sparc/kernel/rtrap_32.S
@@ -0,0 +1,264 @@
+/*
+ * rtrap.S: Return from Sparc trap low-level code.
+ *
+ * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+#include <asm/page.h>
+#include <asm/ptrace.h>
+#include <asm/psr.h>
+#include <asm/asi.h>
+#include <asm/smp.h>
+#include <asm/contregs.h>
+#include <asm/winmacro.h>
+#include <asm/asmmacro.h>
+#include <asm/thread_info.h>
+
+#define t_psr l0
+#define t_pc l1
+#define t_npc l2
+#define t_wim l3
+#define twin_tmp1 l4
+#define glob_tmp g4
+#define curptr g6
+
+ /* 7 WINDOW SPARC PATCH INSTRUCTIONS */
+ .globl rtrap_7win_patch1, rtrap_7win_patch2, rtrap_7win_patch3
+ .globl rtrap_7win_patch4, rtrap_7win_patch5
+rtrap_7win_patch1: srl %t_wim, 0x6, %glob_tmp
+rtrap_7win_patch2: and %glob_tmp, 0x7f, %glob_tmp
+rtrap_7win_patch3: srl %g1, 7, %g2
+rtrap_7win_patch4: srl %g2, 6, %g2
+rtrap_7win_patch5: and %g1, 0x7f, %g1
+ /* END OF PATCH INSTRUCTIONS */
+
+ /* We need to check for a few things which are:
+ * 1) The need to call schedule() because this
+ * processes quantum is up.
+ * 2) Pending signals for this process, if any
+ * exist we need to call do_signal() to do
+ * the needy.
+ *
+ * Else we just check if the rett would land us
+ * in an invalid window, if so we need to grab
+ * it off the user/kernel stack first.
+ */
+
+ .globl ret_trap_entry, rtrap_patch1, rtrap_patch2
+ .globl rtrap_patch3, rtrap_patch4, rtrap_patch5
+ .globl ret_trap_lockless_ipi
+ret_trap_entry:
+ret_trap_lockless_ipi:
+ andcc %t_psr, PSR_PS, %g0
+ sethi %hi(PSR_SYSCALL), %g1
+ be 1f
+ andn %t_psr, %g1, %t_psr
+
+ wr %t_psr, 0x0, %psr
+ b ret_trap_kernel
+ nop
+
+1:
+ ld [%curptr + TI_FLAGS], %g2
+ andcc %g2, (_TIF_NEED_RESCHED), %g0
+ be signal_p
+ nop
+
+ call schedule
+ nop
+
+ ld [%curptr + TI_FLAGS], %g2
+signal_p:
+ andcc %g2, _TIF_DO_NOTIFY_RESUME_MASK, %g0
+ bz,a ret_trap_continue
+ ld [%sp + STACKFRAME_SZ + PT_PSR], %t_psr
+
+ mov %g2, %o2
+ mov %l5, %o1
+ call do_notify_resume
+ add %sp, STACKFRAME_SZ, %o0 ! pt_regs ptr
+
+ b signal_p
+ ld [%curptr + TI_FLAGS], %g2
+
+ret_trap_continue:
+ sethi %hi(PSR_SYSCALL), %g1
+ andn %t_psr, %g1, %t_psr
+ wr %t_psr, 0x0, %psr
+ WRITE_PAUSE
+
+ ld [%curptr + TI_W_SAVED], %twin_tmp1
+ orcc %g0, %twin_tmp1, %g0
+ be ret_trap_nobufwins
+ nop
+
+ wr %t_psr, PSR_ET, %psr
+ WRITE_PAUSE
+
+ mov 1, %o1
+ call try_to_clear_window_buffer
+ add %sp, STACKFRAME_SZ, %o0
+
+ b signal_p
+ ld [%curptr + TI_FLAGS], %g2
+
+ret_trap_nobufwins:
+ /* Load up the user's out registers so we can pull
+ * a window from the stack, if necessary.
+ */
+ LOAD_PT_INS(sp)
+
+ /* If there are already live user windows in the
+ * set we can return from trap safely.
+ */
+ ld [%curptr + TI_UWINMASK], %twin_tmp1
+ orcc %g0, %twin_tmp1, %g0
+ bne ret_trap_userwins_ok
+ nop
+
+ /* Calculate new %wim, we have to pull a register
+ * window from the users stack.
+ */
+ret_trap_pull_one_window:
+ rd %wim, %t_wim
+ sll %t_wim, 0x1, %twin_tmp1
+rtrap_patch1: srl %t_wim, 0x7, %glob_tmp
+ or %glob_tmp, %twin_tmp1, %glob_tmp
+rtrap_patch2: and %glob_tmp, 0xff, %glob_tmp
+
+ wr %glob_tmp, 0x0, %wim
+
+ /* Here comes the architecture specific
+ * branch to the user stack checking routine
+ * for return from traps.
+ */
+ b srmmu_rett_stackchk
+ andcc %fp, 0x7, %g0
+
+ret_trap_userwins_ok:
+ LOAD_PT_PRIV(sp, t_psr, t_pc, t_npc)
+ or %t_pc, %t_npc, %g2
+ andcc %g2, 0x3, %g0
+ sethi %hi(PSR_SYSCALL), %g2
+ be 1f
+ andn %t_psr, %g2, %t_psr
+
+ b ret_trap_unaligned_pc
+ add %sp, STACKFRAME_SZ, %o0
+
+1:
+ LOAD_PT_YREG(sp, g1)
+ LOAD_PT_GLOBALS(sp)
+
+ wr %t_psr, 0x0, %psr
+ WRITE_PAUSE
+
+ jmp %t_pc
+ rett %t_npc
+
+ret_trap_unaligned_pc:
+ ld [%sp + STACKFRAME_SZ + PT_PC], %o1
+ ld [%sp + STACKFRAME_SZ + PT_NPC], %o2
+ ld [%sp + STACKFRAME_SZ + PT_PSR], %o3
+
+ wr %t_wim, 0x0, %wim ! or else...
+
+ wr %t_psr, PSR_ET, %psr
+ WRITE_PAUSE
+
+ call do_memaccess_unaligned
+ nop
+
+ b signal_p
+ ld [%curptr + TI_FLAGS], %g2
+
+ret_trap_kernel:
+ /* Will the rett land us in the invalid window? */
+ mov 2, %g1
+ sll %g1, %t_psr, %g1
+rtrap_patch3: srl %g1, 8, %g2
+ or %g1, %g2, %g1
+ rd %wim, %g2
+ andcc %g2, %g1, %g0
+ be 1f ! Nope, just return from the trap
+ sll %g2, 0x1, %g1
+
+ /* We have to grab a window before returning. */
+rtrap_patch4: srl %g2, 7, %g2
+ or %g1, %g2, %g1
+rtrap_patch5: and %g1, 0xff, %g1
+
+ wr %g1, 0x0, %wim
+
+ /* Grrr, make sure we load from the right %sp... */
+ LOAD_PT_ALL(sp, t_psr, t_pc, t_npc, g1)
+
+ restore %g0, %g0, %g0
+ LOAD_WINDOW(sp)
+ b 2f
+ save %g0, %g0, %g0
+
+ /* Reload the entire frame in case this is from a
+ * kernel system call or whatever...
+ */
+1:
+ LOAD_PT_ALL(sp, t_psr, t_pc, t_npc, g1)
+2:
+ sethi %hi(PSR_SYSCALL), %twin_tmp1
+ andn %t_psr, %twin_tmp1, %t_psr
+ wr %t_psr, 0x0, %psr
+ WRITE_PAUSE
+
+ jmp %t_pc
+ rett %t_npc
+
+ret_trap_user_stack_is_bolixed:
+ wr %t_wim, 0x0, %wim
+
+ wr %t_psr, PSR_ET, %psr
+ WRITE_PAUSE
+
+ call window_ret_fault
+ add %sp, STACKFRAME_SZ, %o0
+
+ b signal_p
+ ld [%curptr + TI_FLAGS], %g2
+
+ .globl srmmu_rett_stackchk
+srmmu_rett_stackchk:
+ bne ret_trap_user_stack_is_bolixed
+ sethi %hi(PAGE_OFFSET), %g1
+ cmp %g1, %fp
+ bleu ret_trap_user_stack_is_bolixed
+ mov AC_M_SFSR, %g1
+LEON_PI(lda [%g1] ASI_LEON_MMUREGS, %g0)
+SUN_PI_(lda [%g1] ASI_M_MMUREGS, %g0)
+
+LEON_PI(lda [%g0] ASI_LEON_MMUREGS, %g1)
+SUN_PI_(lda [%g0] ASI_M_MMUREGS, %g1)
+ or %g1, 0x2, %g1
+LEON_PI(sta %g1, [%g0] ASI_LEON_MMUREGS)
+SUN_PI_(sta %g1, [%g0] ASI_M_MMUREGS)
+
+ restore %g0, %g0, %g0
+
+ LOAD_WINDOW(sp)
+
+ save %g0, %g0, %g0
+
+ andn %g1, 0x2, %g1
+LEON_PI(sta %g1, [%g0] ASI_LEON_MMUREGS)
+SUN_PI_(sta %g1, [%g0] ASI_M_MMUREGS)
+
+ mov AC_M_SFAR, %g2
+LEON_PI(lda [%g2] ASI_LEON_MMUREGS, %g2)
+SUN_PI_(lda [%g2] ASI_M_MMUREGS, %g2)
+
+ mov AC_M_SFSR, %g1
+LEON_PI(lda [%g1] ASI_LEON_MMUREGS, %g1)
+SUN_PI_(lda [%g1] ASI_M_MMUREGS, %g1)
+ andcc %g1, 0x2, %g0
+ be ret_trap_userwins_ok
+ nop
+
+ b,a ret_trap_user_stack_is_bolixed