[PATCH v3 06/12] asm-generic: Define CONFIG_HAVE_FUNCTION_DESCRIPTORS
From: Christophe Leroy
Date: Sun Oct 17 2021 - 08:40:31 EST
Replace HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR by a config option
named CONFIG_HAVE_FUNCTION_DESCRIPTORS and use it instead of
'dereference_function_descriptor' macro to know whether an
arch has function descriptors.
To limit churn in one of the following patches, use
an #ifdef/#else construct with empty first part
instead of an #ifndef in asm-generic/sections.h
On powerpc, make sure the config option matches the ABI used
by the compiler with a BUILD_BUG_ON().
And include a helper to check whether an arch has function
descriptors or not : have_function_descriptors()
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Nicholas Piggin <npiggin@xxxxxxxxx>
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/Kconfig | 3 +++
arch/ia64/Kconfig | 1 +
arch/ia64/include/asm/sections.h | 2 --
arch/parisc/Kconfig | 1 +
arch/parisc/include/asm/sections.h | 2 --
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/sections.h | 2 --
arch/powerpc/kernel/ptrace/ptrace.c | 6 ++++++
include/asm-generic/sections.h | 8 +++++++-
include/linux/kallsyms.h | 2 +-
10 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index 8df1c7102643..6e610a53d832 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -197,6 +197,9 @@ config HAVE_FUNCTION_ERROR_INJECTION
config HAVE_NMI
bool
+config HAVE_FUNCTION_DESCRIPTORS
+ bool
+
config TRACE_IRQFLAGS_SUPPORT
bool
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 1e33666fa679..97cf02951610 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -34,6 +34,7 @@ config IA64
select HAVE_FUNCTION_TRACER
select TTY
select HAVE_ARCH_TRACEHOOK
+ select HAVE_FUNCTION_DESCRIPTORS
select HAVE_VIRT_CPU_ACCOUNTING
select HUGETLB_PAGE_SIZE_VARIABLE if HUGETLB_PAGE
select VIRT_TO_BUS
diff --git a/arch/ia64/include/asm/sections.h b/arch/ia64/include/asm/sections.h
index 35f24e52149a..2460d365a057 100644
--- a/arch/ia64/include/asm/sections.h
+++ b/arch/ia64/include/asm/sections.h
@@ -27,8 +27,6 @@ extern char __start_gate_brl_fsys_bubble_down_patchlist[], __end_gate_brl_fsys_b
extern char __start_unwind[], __end_unwind[];
extern char __start_ivt_text[], __end_ivt_text[];
-#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
-
#undef dereference_function_descriptor
static inline void *dereference_function_descriptor(void *ptr)
{
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 27a8b49af11f..01d46ca32119 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -65,6 +65,7 @@ config PARISC
select HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_SOFTIRQ_ON_OWN_STACK if IRQSTACKS
select TRACE_IRQFLAGS_SUPPORT
+ select HAVE_FUNCTION_DESCRIPTORS if 64BIT
help
The PA-RISC microprocessor is designed by Hewlett-Packard and used
diff --git a/arch/parisc/include/asm/sections.h b/arch/parisc/include/asm/sections.h
index bb52aea0cb21..c8092e4d94de 100644
--- a/arch/parisc/include/asm/sections.h
+++ b/arch/parisc/include/asm/sections.h
@@ -9,8 +9,6 @@ extern char __alt_instructions[], __alt_instructions_end[];
#ifdef CONFIG_64BIT
-#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
-
#undef dereference_function_descriptor
void *dereference_function_descriptor(void *);
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index ba5b66189358..0effedba082f 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -208,6 +208,7 @@ config PPC
select HAVE_EFFICIENT_UNALIGNED_ACCESS if !(CPU_LITTLE_ENDIAN && POWER7_CPU)
select HAVE_FAST_GUP
select HAVE_FTRACE_MCOUNT_RECORD
+ select HAVE_FUNCTION_DESCRIPTORS if PPC64 && !CPU_LITTLE_ENDIAN
select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_TRACER
diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
index abd2e5213197..fb11544d7e6a 100644
--- a/arch/powerpc/include/asm/sections.h
+++ b/arch/powerpc/include/asm/sections.h
@@ -69,8 +69,6 @@ static inline int overlaps_kernel_text(unsigned long start, unsigned long end)
#ifdef PPC64_ELF_ABI_v1
-#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
-
#undef dereference_function_descriptor
static inline void *dereference_function_descriptor(void *ptr)
{
diff --git a/arch/powerpc/kernel/ptrace/ptrace.c b/arch/powerpc/kernel/ptrace/ptrace.c
index 7c7093c17c45..740b682caa73 100644
--- a/arch/powerpc/kernel/ptrace/ptrace.c
+++ b/arch/powerpc/kernel/ptrace/ptrace.c
@@ -446,4 +446,10 @@ void __init pt_regs_check(void)
* real registers.
*/
BUILD_BUG_ON(PT_DSCR < sizeof(struct user_pt_regs) / sizeof(unsigned long));
+
+#ifdef PPC64_ELF_ABI_v1
+ BUILD_BUG_ON(!IS_ENABLED(CONFIG_HAVE_FUNCTION_DESCRIPTORS));
+#else
+ BUILD_BUG_ON(IS_ENABLED(CONFIG_HAVE_FUNCTION_DESCRIPTORS));
+#endif
}
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index d16302d3eb59..a918388d9bf6 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -59,11 +59,17 @@ extern char __noinstr_text_start[], __noinstr_text_end[];
extern __visible const void __nosave_begin, __nosave_end;
/* Function descriptor handling (if any). Override in asm/sections.h */
-#ifndef dereference_function_descriptor
+#ifdef CONFIG_HAVE_FUNCTION_DESCRIPTORS
+#else
#define dereference_function_descriptor(p) ((void *)(p))
#define dereference_kernel_function_descriptor(p) ((void *)(p))
#endif
+static inline bool have_function_descriptors(void)
+{
+ return IS_ENABLED(CONFIG_HAVE_FUNCTION_DESCRIPTORS);
+}
+
/* random extra sections (if any). Override
* in asm/sections.h */
#ifndef arch_is_kernel_text
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index a1d6fc82d7f0..18799df0c9bf 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -57,7 +57,7 @@ static inline int is_ksym_addr(unsigned long addr)
static inline void *dereference_symbol_descriptor(void *ptr)
{
-#ifdef HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR
+#ifdef CONFIG_HAVE_FUNCTION_DESCRIPTORS
struct module *mod;
ptr = dereference_kernel_function_descriptor(ptr);
--
2.31.1