[PATCH] Added ability to vmalloc executable memory

Xander Moerkerken
2022-12-09T13:11:12Z

From: Xander Moerkerken <xander.moerkerken@gmail.com>

Since release 5.8-rc1 the pgprot got removed from __vmalloc
because the only usage was PAGE_KERNEL as argument.
However, this removes the ability to input other arguments
such as 'PAGE_KERNEL_EXEC', which can be used to allocate
memory in which you can execute. For this reason a new
function is introduced called '__vmalloc_exec'.

Signed-off-by: Xander Moerkerken <xander.moerkerken@omron.com>
---
include/linux/vmalloc.h | 1 +
mm/vmalloc.c | 8 ++++++++
2 files changed, 9 insertions(+)

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 096d48aa3437..10c46513b6b2 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -147,6 +147,7 @@ extern void *vzalloc_node(unsigned long size, int node) __alloc_size(1);
extern void *vmalloc_32(unsigned long size) __alloc_size(1);
extern void *vmalloc_32_user(unsigned long size) __alloc_size(1);
extern void *__vmalloc(unsigned long size, gfp_t gfp_mask) __alloc_size(1);
+extern void *__vmalloc_exec(unsigned long size, gfp_t gfp_mask) __alloc_size(1);
extern void *__vmalloc_node_range(unsigned long size, unsigned long align,
unsigned long start, unsigned long end, gfp_t gfp_mask,
pgprot_t prot, unsigned long vm_flags, int node,
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index ccaa461998f3..8fd01ed7082b 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3294,6 +3294,14 @@ void *__vmalloc(unsigned long size, gfp_t gfp_mask)
}
EXPORT_SYMBOL(__vmalloc);

+
+void *__vmalloc_exec(unsigned long size, gfp_t gfp_mask)
+{
+ return __vmalloc_node_prot(size, 1, gfp_mask, PAGE_KERNEL_EXEC,
+ NUMA_NO_NODE, __builtin_return_address(0));
+}
+EXPORT_SYMBOL(__vmalloc_exec);
+
/**
* vmalloc - allocate virtually contiguous memory
* @size: allocation size
--
2.37.2