On Sun, 2017-05-28 at 16:29 +0200, christophe leroy wrote:

Le 25/05/2017 à 05:36, Balbir Singh a écrit :

quoted

Today our patching happens via direct copy and
patch_instruction. The patching code is well
contained in the sense that copying bits are limited.

While considering implementation of CONFIG_STRICT_RWX,
the first requirement is to a create another mapping
that will allow for patching. We create the window using
text_poke_area, allocated via get_vm_area(), which might
be an overkill. We can do per-cpu stuff as well. The
downside of these patches that patch_instruction is
now synchornized using a lock. Other arches do similar
things, but use fixmaps. The reason for not using
fixmaps is to make use of any randomization in the
future. The code also relies on set_pte_at and pte_clear
to do the appropriate tlb flushing.

Signed-off-by: Balbir Singh <bsingharora@gmail.com>

[...]

quoted

+static int kernel_map_addr(void *addr)
+{
+	unsigned long pfn;
 	int err;

-	__put_user_size(instr, addr, 4, err);
+	if (is_vmalloc_addr(addr))
+		pfn = vmalloc_to_pfn(addr);
+	else
+		pfn = __pa_symbol(addr) >> PAGE_SHIFT;
+
+	err = map_kernel_page((unsigned long)text_poke_area->addr,
+			(pfn << PAGE_SHIFT), _PAGE_KERNEL_RW | _PAGE_PRESENT);

map_kernel_page() doesn't exist on powerpc32, so compilation fails.

However a similar function exists and is called map_page()

Maybe the below modification could help (not tested yet)

Christophe

Thanks, I'll try and get a compile, as an alternative how about

#ifdef CONFIG_PPC32
#define map_kernel_page map_page
#endif

Balbir Singh.