X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=src%2Fwrapper%2Fkallsyms.c;h=2535c2a527faed90f20909ce809334adaae28169;hb=b4a626cb684d2797df0329dd80c2df95e490c621;hp=6af77f538950d7b3718bd33fffb749053ae03333;hpb=cfa6cc1d0f01c2cfcc1a679abf3a6572d411c309;p=lttng-modules.git

diff --git a/src/wrapper/kallsyms.c b/src/wrapper/kallsyms.c
index 6af77f53..2535c2a5 100644
--- a/src/wrapper/kallsyms.c
+++ b/src/wrapper/kallsyms.c
@@ -14,7 +14,7 @@
 #include <linux/module.h>
 #include <wrapper/kallsyms.h>
 
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,7,0))
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,7,0))
 
 #ifndef CONFIG_KPROBES
 # error "LTTng-modules requires CONFIG_KPROBES on kernels >= 5.7.0"
@@ -29,6 +29,80 @@ int dummy_kprobe_handler(struct kprobe *p, struct pt_regs *regs)
 	return 0;
 }
 
+#ifdef LTTNG_CONFIG_PPC64_ELF_ABI_V2
+static
+void kallsyms_pre_arch_adjust(struct kprobe *probe)
+{
+	/*
+	 * With powerpc64 ABIv2, we need the global entry point of
+	 * kallsyms_lookup_name to call it later, while kprobe_register would
+	 * automatically adjust the global entry point to the local entry point,
+	 * when a kprobe was registered at a function entry. So we add 4 bytes
+	 * which is the length of one instruction to kallsyms_lookup_name to
+	 * avoid the adjustment.
+	 */
+	probe->offset = 4;
+}
+#else
+static
+void kallsyms_pre_arch_adjust(struct kprobe *probe)
+{
+}
+#endif
+
+#ifdef LTTNG_CONFIG_PPC64_ELF_ABI_V2
+static
+unsigned long kallsyms_get_arch_call_addr(const struct kprobe *probe)
+{
+	/* Substract 4 bytes to get what we originally want */
+	return (unsigned long)(((char *)probe->addr) - 4);
+}
+
+#elif defined(LTTNG_CONFIG_PPC64_ELF_ABI_V1)
+# if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,18,0))
+# include <asm/elf.h>
+# define LTTNG_FUNC_DESC_TYPE struct func_desc
+# define LTTNG_FUNC_DESC_ADDR_NAME addr
+# else
+# include <asm/types.h>
+# define LTTNG_FUNC_DESC_TYPE func_descr_t
+# define LTTNG_FUNC_DESC_ADDR_NAME entry
+
+static
+LTTNG_FUNC_DESC_TYPE kallsyms_lookup_name_func_desc;
+# endif
+
+static
+unsigned long kallsyms_get_arch_call_addr(const struct kprobe *probe)
+{
+	/*
+	 * Build a function descriptor from the address of
+	 * 'kallsyms_lookup_name' returned by kprobe and the toc of
+	 * 'sprint_symbol' which is in the same compile unit and exported. I
+	 * hate this on so many levels but it works.
+	 */
+	kallsyms_lookup_name_func_desc.LTTNG_FUNC_DESC_ADDR_NAME = (unsigned long) probe.addr;
+	kallsyms_lookup_name_func_desc.toc = ((LTTNG_FUNC_DESC_TYPE *) &sprint_symbol)->toc;
+	return (unsigned long) &kallsyms_lookup_name_func_desc;
+}
+#elif defined(CONFIG_ARM) && defined(CONFIG_THUMB2_KERNEL)
+static
+unsigned long kallsyms_get_arch_call_addr(const struct kprobe *probe)
+{
+	unsigned long addr = (unsigned long)probe->addr;
+
+	if (addr)
+		addr |= 1; /* set bit 0 in address for thumb mode */
+	return addr;
+}
+#else
+static
+unsigned long kallsyms_get_arch_call_addr(const struct kprobe *probe)
+{
+	return (unsigned long)probe->addr;
+}
+#endif
+
 static
 unsigned long do_get_kallsyms(void)
 {
@@ -39,16 +113,11 @@ unsigned long do_get_kallsyms(void)
 	memset(&probe, 0, sizeof(probe));
 	probe.pre_handler = dummy_kprobe_handler;
 	probe.symbol_name = "kallsyms_lookup_name";
+	kallsyms_pre_arch_adjust(&probe);
 	ret = register_kprobe(&probe);
 	if (ret)
 		return 0;
-	addr = (unsigned long)probe.addr;
-#ifdef CONFIG_ARM
-#ifdef CONFIG_THUMB2_KERNEL
-	if (addr)
-		addr |= 1; /* set bit 0 in address for thumb mode */
-#endif
-#endif
+	addr = kallsyms_get_arch_call_addr(&probe);
 	unregister_kprobe(&probe);
 	return addr;
 }
@@ -61,10 +130,14 @@ unsigned long wrapper_kallsyms_lookup_name(const char *name)
 	if (kallsyms_lookup_name_sym)
 		return kallsyms_lookup_name_sym(name);
 	else {
-		printk_once(KERN_WARNING "LTTng requires kallsyms_lookup_name\n");
+		printk_once(KERN_WARNING "LTTng: requires kallsyms_lookup_name\n");
 		return 0;
 	}
 }
 EXPORT_SYMBOL_GPL(wrapper_kallsyms_lookup_name);
 
 #endif
+
+#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,4,0) && defined(CONFIG_ANDROID))
+MODULE_IMPORT_NS(VFS_internal_I_am_really_a_filesystem_and_am_NOT_a_driver);
+#endif