Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 87 insertions, 0 deletions

diff --git a/arch/ia64/kernel/efi_stub.S b/arch/ia64/kernel/efi_stub.S
new file mode 100644
index 000000000..58233bb79
--- /dev/null
+++ b/arch/ia64/kernel/efi_stub.S
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * EFI call stub.
+ *
+ * Copyright (C) 1999-2001 Hewlett-Packard Co
+ *	David Mosberger <davidm@hpl.hp.com>
+ *
+ * This stub allows us to make EFI calls in physical mode with interrupts
+ * turned off.  We need this because we can't call SetVirtualMap() until
+ * the kernel has booted far enough to allow allocation of struct vma_struct
+ * entries (which we would need to map stuff with memory attributes other
+ * than uncached or writeback...).  Since the GetTime() service gets called
+ * earlier than that, we need to be able to make physical mode EFI calls from
+ * the kernel.
+ */
+
+/*
+ * PSR settings as per SAL spec (Chapter 8 in the "IA-64 System
+ * Abstraction Layer Specification", revision 2.6e).  Note that
+ * psr.dfl and psr.dfh MUST be cleared, despite what this manual says.
+ * Otherwise, SAL dies whenever it's trying to do an IA-32 BIOS call
+ * (the br.ia instruction fails unless psr.dfl and psr.dfh are
+ * cleared).  Fortunately, SAL promises not to touch the floating
+ * point regs, so at least we don't have to save f2-f127.
+ */
+#define PSR_BITS_TO_CLEAR						\
+	(IA64_PSR_I | IA64_PSR_IT | IA64_PSR_DT | IA64_PSR_RT |		\
+	 IA64_PSR_DD | IA64_PSR_SS | IA64_PSR_RI | IA64_PSR_ED |	\
+	 IA64_PSR_DFL | IA64_PSR_DFH)
+
+#define PSR_BITS_TO_SET							\
+	(IA64_PSR_BN)
+
+#include <asm/processor.h>
+#include <asm/asmmacro.h>
+
+/*
+ * Inputs:
+ *	in0 = address of function descriptor of EFI routine to call
+ *	in1..in7 = arguments to routine
+ *
+ * Outputs:
+ *	r8 = EFI_STATUS returned by called function
+ */
+
+GLOBAL_ENTRY(efi_call_phys)
+	.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
+	alloc loc1=ar.pfs,8,7,7,0
+	ld8 r2=[in0],8			// load EFI function's entry point
+	mov loc0=rp
+	.body
+	;;
+	mov loc2=gp			// save global pointer
+	mov loc4=ar.rsc			// save RSE configuration
+	mov ar.rsc=0			// put RSE in enforced lazy, LE mode
+	;;
+	ld8 gp=[in0]			// load EFI function's global pointer
+	movl r16=PSR_BITS_TO_CLEAR
+	mov loc3=psr			// save processor status word
+	movl r17=PSR_BITS_TO_SET
+	;;
+	or loc3=loc3,r17
+	mov b6=r2
+	;;
+	andcm r16=loc3,r16	// get psr with IT, DT, and RT bits cleared
+	br.call.sptk.many rp=ia64_switch_mode_phys
+.ret0:	mov out4=in5
+	mov out0=in1
+	mov out1=in2
+	mov out2=in3
+	mov out3=in4
+	mov out5=in6
+	mov out6=in7
+	mov loc5=r19
+	mov loc6=r20
+	br.call.sptk.many rp=b6		// call the EFI function
+.ret1:	mov ar.rsc=0			// put RSE in enforced lazy, LE mode
+	mov r16=loc3
+	mov r19=loc5
+	mov r20=loc6
+	br.call.sptk.many rp=ia64_switch_mode_virt // return to virtual mode
+.ret2:	mov ar.rsc=loc4			// restore RSE configuration
+	mov ar.pfs=loc1
+	mov rp=loc0
+	mov gp=loc2
+	br.ret.sptk.many rp
+END(efi_call_phys)