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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v1 1/4] xen: introduce CONFIG_GENERIC_BUG_FRAME
A large part of the content of the bug.h is repeated among all
architectures, so it was decided to create a new config
CONFIG_GENERIC_BUG_FRAME.
The version of <bug.h> from ARM was taken as the base version,
as it looks the most portable.
The patch introduces the following stuff:
* common bug.h header
* generic implementation of do_bug_frame()
* new config CONFIG_GENERIC_BUG_FRAME
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
xen/common/Kconfig | 6 ++
xen/common/Makefile | 1 +
xen/common/bug.c | 88 +++++++++++++++++++++++++++++
xen/include/xen/bug.h | 127 ++++++++++++++++++++++++++++++++++++++++++
4 files changed, 222 insertions(+)
create mode 100644 xen/common/bug.c
create mode 100644 xen/include/xen/bug.h
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index f1ea3199c8..811b4eaf3b 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -92,6 +92,12 @@ config STATIC_MEMORY
If unsure, say N.
+config GENERIC_DO_BUG_FRAME
+ bool
+ help
+ Generic do_bug_frame() function is needed to handle the type of bug
+ frame and print an information about it.
+
menu "Speculative hardening"
config INDIRECT_THUNK
diff --git a/xen/common/Makefile b/xen/common/Makefile
index bbd75b4be6..7d04c8d3b2 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -1,5 +1,6 @@
obj-$(CONFIG_ARGO) += argo.o
obj-y += bitmap.o
+obj-$(CONFIG_GENERIC_DO_BUG_FRAME) += bug.o
obj-$(CONFIG_HYPFS_CONFIG) += config_data.o
obj-$(CONFIG_CORE_PARKING) += core_parking.o
obj-y += cpu.o
diff --git a/xen/common/bug.c b/xen/common/bug.c
new file mode 100644
index 0000000000..393e58d571
--- /dev/null
+++ b/xen/common/bug.c
@@ -0,0 +1,88 @@
+#include <xen/bug.h>
+#include <xen/errno.h>
+#include <xen/types.h>
+#include <xen/kernel.h>
+#include <xen/string.h>
+#include <xen/virtual_region.h>
+
+#include <asm/processor.h>
+
+int do_bug_frame(const struct cpu_user_regs *regs, vaddr_t pc)
+{
+ const struct bug_frame *bug = NULL;
+ const char *prefix = "", *filename, *predicate;
+ unsigned long fixup;
+ int id = -1, lineno;
+ const struct virtual_region *region;
+
+ region = find_text_region(pc);
+ if ( region )
+ {
+ for ( id = 0; id < BUGFRAME_NR; id++ )
+ {
+ const struct bug_frame *b;
+ unsigned int i;
+
+ for ( i = 0, b = region->frame[id].bugs;
+ i < region->frame[id].n_bugs; b++, i++ )
+ {
+ if ( ((vaddr_t)bug_loc(b)) == pc )
+ {
+ bug = b;
+ goto found;
+ }
+ }
+ }
+ }
+ found:
+ if ( !bug )
+ return -ENOENT;
+
+ if ( id == BUGFRAME_run_fn )
+ {
+ void (*fn)(const struct cpu_user_regs *) = (void *)regs->BUG_FN_REG;
+
+ fn(regs);
+ return 0;
+ }
+
+ /* WARN, BUG or ASSERT: decode the filename pointer and line number. */
+ filename = bug_file(bug);
+ if ( !is_kernel(filename) )
+ return -EINVAL;
+ fixup = strlen(filename);
+ if ( fixup > 50 )
+ {
+ filename += fixup - 47;
+ prefix = "...";
+ }
+ lineno = bug_line(bug);
+
+ switch ( id )
+ {
+ case BUGFRAME_warn:
+ printk("Xen WARN at %s%s:%d\n", prefix, filename, lineno);
+ show_execution_state(regs);
+ return 0;
+
+ case BUGFRAME_bug:
+ printk("Xen BUG at %s%s:%d\n", prefix, filename, lineno);
+ show_execution_state(regs);
+ panic("Xen BUG at %s%s:%d\n", prefix, filename, lineno);
+
+ case BUGFRAME_assert:
+ /* ASSERT: decode the predicate string pointer. */
+ predicate = bug_msg(bug);
+ if ( !is_kernel(predicate) )
+ predicate = "<unknown>";
+
+ printk("Assertion '%s' failed at %s%s:%d\n",
+ predicate, prefix, filename, lineno);
+ show_execution_state(regs);
+ panic("Assertion '%s' failed at %s%s:%d\n",
+ predicate, prefix, filename, lineno);
+ }
+
+ return -EINVAL;
+}
+
diff --git a/xen/include/xen/bug.h b/xen/include/xen/bug.h
new file mode 100644
index 0000000000..b46dae035e
--- /dev/null
+++ b/xen/include/xen/bug.h
@@ -0,0 +1,127 @@
+#ifndef __XEN_BUG_H__
+#define __XEN_BUG_H__
+
+#define BUG_DISP_WIDTH 24
+#define BUG_LINE_LO_WIDTH (31 - BUG_DISP_WIDTH)
+#define BUG_LINE_HI_WIDTH (31 - BUG_DISP_WIDTH)
+
+#define BUGFRAME_run_fn 0
+#define BUGFRAME_warn 1
+#define BUGFRAME_bug 2
+#define BUGFRAME_assert 3
+
+#define BUGFRAME_NR 4
+
+#ifndef __ASSEMBLY__
+
+#include <xen/errno.h>
+#include <xen/stringify.h>
+#include <xen/types.h>
+#include <xen/lib.h>
+
+#include <asm/bug.h>
+
+#ifndef BUG_FRAME_STUFF
+struct bug_frame {
+ signed int loc_disp; /* Relative address to the bug address */
+ signed int file_disp; /* Relative address to the filename */
+ signed int msg_disp; /* Relative address to the predicate (for ASSERT)
*/
+ uint16_t line; /* Line number */
+ uint32_t pad0:16; /* Padding for 8-bytes align */
+};
+
+#define bug_loc(b) ((const void *)(b) + (b)->loc_disp)
+#define bug_file(b) ((const void *)(b) + (b)->file_disp);
+#define bug_line(b) ((b)->line)
+#define bug_msg(b) ((const char *)(b) + (b)->msg_disp)
+#endif /* BUG_FRAME_STUFF */
+
+#ifndef BUG_FRAME
+/* Many versions of GCC doesn't support the asm %c parameter which would
+ * be preferable to this unpleasantness. We use mergeable string
+ * sections to avoid multiple copies of the string appearing in the
+ * Xen image. BUGFRAME_run_fn needs to be handled separately.
+ */
+#define BUG_FRAME(type, line, file, has_msg, msg) do { \
+ BUILD_BUG_ON((line) >> 16); \
+ BUILD_BUG_ON((type) >= BUGFRAME_NR); \
+ asm ("1:"BUG_INSTR"\n" \
+ ".pushsection .rodata.str, \"aMS\", %progbits, 1\n" \
+ "2:\t.asciz " __stringify(file) "\n" \
+ "3:\n" \
+ ".if " #has_msg "\n" \
+ "\t.asciz " #msg "\n" \
+ ".endif\n" \
+ ".popsection\n" \
+ ".pushsection .bug_frames." __stringify(type) ", \"a\", %progbits\n"\
+ "4:\n" \
+ ".p2align 2\n" \
+ ".long (1b - 4b)\n" \
+ ".long (2b - 4b)\n" \
+ ".long (3b - 4b)\n" \
+ ".hword " __stringify(line) ", 0\n" \
+ ".popsection"); \
+} while (0)
+#endif /* BUG_FRAME */
+
+#ifndef run_in_exception_handler
+/*
+ * GCC will not allow to use "i" when PIE is enabled (Xen doesn't set the
+ * flag but instead rely on the default value from the compiler). So the
+ * easiest way to implement run_in_exception_handler() is to pass the to
+ * be called function in a fixed register.
+ */
+#define run_in_exception_handler(fn) do { \
+ register void *fn_ asm(__stringify(BUG_FN_REG)) = (fn); \
+ asm ("1:"BUG_INSTR"\n" \
+ ".pushsection .bug_frames." __stringify(BUGFRAME_run_fn) "," \
+ " \"a\", %%progbits\n" \
+ "2:\n" \
+ ".p2align 2\n" \
+ ".long (1b - 2b)\n" \
+ ".long 0, 0, 0\n" \
+ ".popsection" :: "r" (fn_)); \
+} while (0)
+#endif /* run_in_exception_handler */
+
+#ifndef WARN
+#define WARN() BUG_FRAME(BUGFRAME_warn, __LINE__, __FILE__, 0, "")
+#endif /* WARN */
+
+#ifndef BUG
+#define BUG() do { \
+ BUG_FRAME(BUGFRAME_bug, __LINE__, __FILE__, 0, ""); \
+ unreachable(); \
+} while (0)
+#endif
+
+#ifndef assert_failed
+#define assert_failed(msg) do { \
+ BUG_FRAME(BUGFRAME_assert, __LINE__, __FILE__, 1, msg); \
+ unreachable(); \
+} while (0)
+#endif
+
+extern const struct bug_frame __start_bug_frames[],
+ __stop_bug_frames_0[],
+ __stop_bug_frames_1[],
+ __stop_bug_frames_2[],
+ __stop_bug_frames_3[];
+
+#else /* !__ASSEMBLY__ */
+
+#ifdef CONFIG_X86
+#include <asm/bug.h>
+#endif
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __XEN_BUG_H__ */
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
--
2.39.0
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