treewide: Drop function_nocfi

With -fsanitize=kcfi, we no longer need function_nocfi() as
the compiler won't change function references to point to a
jump table. Remove all implementations and uses of the macro.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-14-samitolvanen@google.com

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index dbc45a4..329dbbd 100644 (file)
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -26,7 +26,7 @@
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 #define ARCH_SUPPORTS_FTRACE_OPS 1
 #else
-#define MCOUNT_ADDR            ((unsigned long)function_nocfi(_mcount))
+#define MCOUNT_ADDR            ((unsigned long)_mcount)
 #endif
 
 /* The BL at the callsite's adjusted rec->ip */

diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h
index bba0e63..d3f8b5d 100644 (file)
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h
@@ -168,7 +168,7 @@ static inline void cpu_replace_ttbr1(pgd_t *pgdp, pgd_t *idmap)
                ttbr1 |= TTBR_CNP_BIT;
        }
 
-       replace_phys = (void *)__pa_symbol(function_nocfi(idmap_cpu_replace_ttbr1));
+       replace_phys = (void *)__pa_symbol(idmap_cpu_replace_ttbr1);
 
        __cpu_install_idmap(idmap);
        replace_phys(ttbr1);

diff --git a/arch/arm64/kernel/acpi_parking_protocol.c b/arch/arm64/kernel/acpi_parking_protocol.c
index bfeeb53..b1990e3 100644 (file)
--- a/arch/arm64/kernel/acpi_parking_protocol.c
+++ b/arch/arm64/kernel/acpi_parking_protocol.c
@@ -99,7 +99,7 @@ static int acpi_parking_protocol_cpu_boot(unsigned int cpu)
         * that read this address need to convert this address to the
         * Boot-Loader's endianness before jumping.
         */
-       writeq_relaxed(__pa_symbol(function_nocfi(secondary_entry)),
+       writeq_relaxed(__pa_symbol(secondary_entry),
                       &mailbox->entry_point);
        writel_relaxed(cpu_entry->gic_cpu_id, &mailbox->cpu_id);
 

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index ca6e5ca..d836169 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1713,7 +1713,7 @@ kpti_install_ng_mappings(const struct arm64_cpu_capabilities *__unused)
        if (arm64_use_ng_mappings)
                return;
 
-       remap_fn = (void *)__pa_symbol(function_nocfi(idmap_kpti_install_ng_mappings));
+       remap_fn = (void *)__pa_symbol(idmap_kpti_install_ng_mappings);
 
        if (!cpu) {
                alloc = __get_free_pages(GFP_ATOMIC | __GFP_ZERO, order);

diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index ea5dc7c..2678986 100644 (file)
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -56,7 +56,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
        unsigned long pc;
        u32 new;
 
-       pc = (unsigned long)function_nocfi(ftrace_call);
+       pc = (unsigned long)ftrace_call;
        new = aarch64_insn_gen_branch_imm(pc, (unsigned long)func,
                                          AARCH64_INSN_BRANCH_LINK);
 

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 19c2d48..ce3d401 100644 (file)
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -204,7 +204,7 @@ void machine_kexec(struct kimage *kimage)
                typeof(cpu_soft_restart) *restart;
 
                cpu_install_idmap();
-               restart = (void *)__pa_symbol(function_nocfi(cpu_soft_restart));
+               restart = (void *)__pa_symbol(cpu_soft_restart);
                restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem,
                        0, 0);
        } else {

diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
index ab7f4c4..29a8e44 100644 (file)
--- a/arch/arm64/kernel/psci.c
+++ b/arch/arm64/kernel/psci.c
@@ -38,7 +38,7 @@ static int __init cpu_psci_cpu_prepare(unsigned int cpu)
 
 static int cpu_psci_cpu_boot(unsigned int cpu)
 {
-       phys_addr_t pa_secondary_entry = __pa_symbol(function_nocfi(secondary_entry));
+       phys_addr_t pa_secondary_entry = __pa_symbol(secondary_entry);
        int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry);
        if (err)
                pr_err("failed to boot CPU%d (%d)\n", cpu, err);

diff --git a/arch/arm64/kernel/smp_spin_table.c b/arch/arm64/kernel/smp_spin_table.c
index 7e1624e..49029ea 100644 (file)
--- a/arch/arm64/kernel/smp_spin_table.c
+++ b/arch/arm64/kernel/smp_spin_table.c
@@ -66,7 +66,7 @@ static int smp_spin_table_cpu_init(unsigned int cpu)
 static int smp_spin_table_cpu_prepare(unsigned int cpu)
 {
        __le64 __iomem *release_addr;
-       phys_addr_t pa_holding_pen = __pa_symbol(function_nocfi(secondary_holding_pen));
+       phys_addr_t pa_holding_pen = __pa_symbol(secondary_holding_pen);
 
        if (!cpu_release_addr[cpu])
                return -ENODEV;

diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index 75ef784..bc6b5a1 100644 (file)
--- a/drivers/firmware/psci/psci.c
+++ b/drivers/firmware/psci/psci.c
@@ -334,7 +334,7 @@ static int __init psci_features(u32 psci_func_id)
 static int psci_suspend_finisher(unsigned long state)
 {
        u32 power_state = state;
-       phys_addr_t pa_cpu_resume = __pa_symbol(function_nocfi(cpu_resume));
+       phys_addr_t pa_cpu_resume = __pa_symbol(cpu_resume);
 
        return psci_ops.cpu_suspend(power_state, pa_cpu_resume);
 }
@@ -359,7 +359,7 @@ int psci_cpu_suspend_enter(u32 state)
 
 static int psci_system_suspend(unsigned long unused)
 {
-       phys_addr_t pa_cpu_resume = __pa_symbol(function_nocfi(cpu_resume));
+       phys_addr_t pa_cpu_resume = __pa_symbol(cpu_resume);
 
        return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
                              pa_cpu_resume, 0, 0);

diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c
index 6215ec9..67db572 100644 (file)
--- a/drivers/misc/lkdtm/usercopy.c
+++ b/drivers/misc/lkdtm/usercopy.c
@@ -330,7 +330,7 @@ static void lkdtm_USERCOPY_KERNEL(void)
 
        pr_info("attempting bad copy_to_user from kernel text: %px\n",
                vm_mmap);
-       if (copy_to_user((void __user *)user_addr, function_nocfi(vm_mmap),
+       if (copy_to_user((void __user *)user_addr, vm_mmap,
                         unconst + PAGE_SIZE)) {
                pr_warn("copy_to_user failed, but lacked Oops\n");
                goto free_user;

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 7bfafc6..973a1bf 100644 (file)
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -203,16 +203,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
        __v;                                                            \
 })
 
-/*
- * With CONFIG_CFI_CLANG, the compiler replaces function addresses in
- * instrumented C code with jump table addresses. Architectures that
- * support CFI can define this macro to return the actual function address
- * when needed.
- */
-#ifndef function_nocfi
-#define function_nocfi(x) (x)
-#endif
-
 #endif /* __KERNEL__ */
 
 /*