arch: make execmem setup available regardless of CONFIG_MODULES

execmem does not depend on modules, on the contrary modules use
execmem.

To make execmem available when CONFIG_MODULES=n, for instance for
kprobes, split execmem_params initialization out from
arch/*/kernel/module.c and compile it when CONFIG_EXECMEM=y

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

1 files changed, 64 insertions, 0 deletions

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 3a440004b97d..5de62a3c1d4b 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -16,6 +16,7 @@
 #include <linux/highmem.h>
 #include <linux/suspend.h>
 #include <linux/dma-direct.h>
+#include <linux/execmem.h>
 
 #include <asm/swiotlb.h>
 #include <asm/machdep.h>
@@ -406,3 +407,66 @@ int devmem_is_allowed(unsigned long pfn)
  * the EHEA driver. Drop this when drivers/net/ethernet/ibm/ehea is removed.
  */
 EXPORT_SYMBOL_GPL(walk_system_ram_range);
+
+#ifdef CONFIG_EXECMEM
+static struct execmem_info execmem_info __ro_after_init;
+
+struct execmem_info __init *execmem_arch_setup(void)
+{
+	pgprot_t kprobes_prot = strict_module_rwx_enabled() ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
+	pgprot_t prot = strict_module_rwx_enabled() ? PAGE_KERNEL : PAGE_KERNEL_EXEC;
+	unsigned long fallback_start = 0, fallback_end = 0;
+	unsigned long start, end;
+
+	/*
+	 * BOOK3S_32 and 8xx define MODULES_VADDR for text allocations and
+	 * allow allocating data in the entire vmalloc space
+	 */
+#ifdef MODULES_VADDR
+	unsigned long limit = (unsigned long)_etext - SZ_32M;
+
+	BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
+
+	/* First try within 32M limit from _etext to avoid branch trampolines */
+	if (MODULES_VADDR < PAGE_OFFSET && MODULES_END > limit) {
+		start = limit;
+		fallback_start = MODULES_VADDR;
+		fallback_end = MODULES_END;
+	} else {
+		start = MODULES_VADDR;
+	}
+
+	end = MODULES_END;
+#else
+	start = VMALLOC_START;
+	end = VMALLOC_END;
+#endif
+
+	execmem_info = (struct execmem_info){
+		.ranges = {
+			[EXECMEM_DEFAULT] = {
+				.start	= start,
+				.end	= end,
+				.pgprot	= prot,
+				.alignment = 1,
+				.fallback_start	= fallback_start,
+				.fallback_end	= fallback_end,
+			},
+			[EXECMEM_KPROBES] = {
+				.start	= VMALLOC_START,
+				.end	= VMALLOC_END,
+				.pgprot	= kprobes_prot,
+				.alignment = 1,
+			},
+			[EXECMEM_MODULE_DATA] = {
+				.start	= VMALLOC_START,
+				.end	= VMALLOC_END,
+				.pgprot	= PAGE_KERNEL,
+				.alignment = 1,
+			},
+		},
+	};
+
+	return &execmem_info;
+}
+#endif /* CONFIG_EXECMEM */