Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 172 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/head-64.h b/arch/powerpc/include/asm/head-64.h
new file mode 100644
index 0000000000..d73153b027
--- /dev/null
+++ b/arch/powerpc/include/asm/head-64.h
@@ -0,0 +1,172 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_POWERPC_HEAD_64_H
+#define _ASM_POWERPC_HEAD_64_H
+
+#include <asm/cache.h>
+
+#ifdef __ASSEMBLY__
+/*
+ * We can't do CPP stringification and concatination directly into the section
+ * name for some reason, so these macros can do it for us.
+ */
+.macro define_ftsec name
+	.section ".head.text.\name\()","ax",@progbits
+.endm
+.macro define_data_ftsec name
+	.section ".head.data.\name\()","a",@progbits
+.endm
+.macro use_ftsec name
+	.section ".head.text.\name\()","ax",@progbits
+.endm
+
+/*
+ * Fixed (location) sections are used by opening fixed sections and emitting
+ * fixed section entries into them before closing them. Multiple fixed sections
+ * can be open at any time.
+ *
+ * Each fixed section created in a .S file must have corresponding linkage
+ * directives including location, added to  arch/powerpc/kernel/vmlinux.lds.S
+ *
+ * For each fixed section, code is generated into it in the order which it
+ * appears in the source.  Fixed section entries can be placed at a fixed
+ * location within the section using _LOCATION postifx variants. These must
+ * be ordered according to their relative placements within the section.
+ *
+ * OPEN_FIXED_SECTION(section_name, start_address, end_address)
+ * FIXED_SECTION_ENTRY_BEGIN(section_name, label1)
+ *
+ * USE_FIXED_SECTION(section_name)
+ * label3:
+ *     li  r10,128
+ *     mv  r11,r10
+
+ * FIXED_SECTION_ENTRY_BEGIN_LOCATION(section_name, label2, start_address, size)
+ * FIXED_SECTION_ENTRY_END_LOCATION(section_name, label2, start_address, size)
+ * CLOSE_FIXED_SECTION(section_name)
+ *
+ * ZERO_FIXED_SECTION can be used to emit zeroed data.
+ *
+ * Troubleshooting:
+ * - If the build dies with "Error: attempt to move .org backwards" at
+ *   CLOSE_FIXED_SECTION() or elsewhere, there may be something
+ *   unexpected being added there. Remove the '. = x_len' line, rebuild, and
+ *   check what is pushing the section down.
+ * - If the build dies in linking, check arch/powerpc/tools/head_check.sh
+ *   comments.
+ * - If the kernel crashes or hangs in very early boot, it could be linker
+ *   stubs at the start of the main text.
+ */
+
+#define OPEN_FIXED_SECTION(sname, start, end)			\
+	sname##_start = (start);				\
+	sname##_end = (end);					\
+	sname##_len = (end) - (start);				\
+	define_ftsec sname;					\
+	. = 0x0;						\
+start_##sname:
+
+/*
+ * .linker_stub_catch section is used to catch linker stubs from being
+ * inserted in our .text section, above the start_text label (which breaks
+ * the ABS_ADDR calculation). See kernel/vmlinux.lds.S and tools/head_check.sh
+ * for more details. We would prefer to just keep a cacheline (0x80), but
+ * 0x100 seems to be how the linker aligns branch stub groups.
+ */
+#ifdef CONFIG_LD_HEAD_STUB_CATCH
+#define OPEN_TEXT_SECTION(start)				\
+	.section ".linker_stub_catch","ax",@progbits;		\
+linker_stub_catch:						\
+	. = 0x4;						\
+	text_start = (start) + 0x100;				\
+	.section ".text","ax",@progbits;			\
+	.balign 0x100;						\
+start_text:
+#else
+#define OPEN_TEXT_SECTION(start)				\
+	text_start = (start);					\
+	.section ".text","ax",@progbits;			\
+	. = 0x0;						\
+start_text:
+#endif
+
+#define ZERO_FIXED_SECTION(sname, start, end)			\
+	sname##_start = (start);				\
+	sname##_end = (end);					\
+	sname##_len = (end) - (start);				\
+	define_data_ftsec sname;				\
+	. = 0x0;						\
+	. = sname##_len;
+
+#define USE_FIXED_SECTION(sname)				\
+	use_ftsec sname;
+
+#define USE_TEXT_SECTION()					\
+	.text
+
+#define CLOSE_FIXED_SECTION(sname)				\
+	USE_FIXED_SECTION(sname);				\
+	. = sname##_len;					\
+end_##sname:
+
+
+#define __FIXED_SECTION_ENTRY_BEGIN(sname, name, __align)	\
+	USE_FIXED_SECTION(sname);				\
+	.balign __align;					\
+	.global name;						\
+name:
+
+#define FIXED_SECTION_ENTRY_BEGIN(sname, name)			\
+	__FIXED_SECTION_ENTRY_BEGIN(sname, name, IFETCH_ALIGN_BYTES)
+
+#define FIXED_SECTION_ENTRY_BEGIN_LOCATION(sname, name, start, size) \
+	USE_FIXED_SECTION(sname);				\
+	name##_start = (start);					\
+	.if ((start) % (size) != 0);				\
+	.error "Fixed section exception vector misalignment";	\
+	.endif;							\
+	.if ((size) != 0x20) && ((size) != 0x80) && ((size) != 0x100) && ((size) != 0x1000); \
+	.error "Fixed section exception vector bad size";	\
+	.endif;							\
+	.if (start) < sname##_start;				\
+	.error "Fixed section underflow";			\
+	.abort;							\
+	.endif;							\
+	. = (start) - sname##_start;				\
+	.global name;						\
+name:
+
+#define FIXED_SECTION_ENTRY_END_LOCATION(sname, name, start, size) \
+	.if (start) + (size) > sname##_end;			\
+	.error "Fixed section overflow";			\
+	.abort;							\
+	.endif;							\
+	.if (. - name > (start) + (size) - name##_start);	\
+	.error "Fixed entry overflow";				\
+	.abort;							\
+	.endif;							\
+	. = ((start) + (size) - sname##_start);			\
+
+
+/*
+ * These macros are used to change symbols in other fixed sections to be
+ * absolute or related to our current fixed section.
+ *
+ * - DEFINE_FIXED_SYMBOL / FIXED_SYMBOL_ABS_ADDR is used to find the
+ *   absolute address of a symbol within a fixed section, from any section.
+ *
+ * - ABS_ADDR is used to find the absolute address of any symbol, from within
+ *   a fixed section.
+ */
+// define label as being _in_ sname
+#define DEFINE_FIXED_SYMBOL(label, sname) \
+	label##_absolute = (label - start_ ## sname + sname ## _start)
+
+#define FIXED_SYMBOL_ABS_ADDR(label)				\
+	(label##_absolute)
+
+// find label from _within_ sname
+#define ABS_ADDR(label, sname) (label - start_ ## sname + sname ## _start)
+
+#endif /* __ASSEMBLY__ */
+
+#endif	/* _ASM_POWERPC_HEAD_64_H */