On 10/29/18 12:59 PM, Rob Herring wrote:

+Ard who last touched this.

On Mon, Oct 29, 2018 at 2:23 PM Florian Fainelli [off-list ref] wrote:

quoted

ARM64 is the only architecture that re-defines
__early_init_dt_declare_initrd() in order for that function to populate
initrd_start/initrd_end with physical addresses instead of virtual
addresses. Instead of having an override, just get rid of that
implementation and perform the virtual to physical conversion of these
addresses in arm64_memblock_init() where relevant.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Mike Rapoport <redacted>
---
 arch/arm64/include/asm/memory.h |  8 -------
 arch/arm64/mm/init.c            | 42 +++++++++++++++++++++------------
 2 files changed, 27 insertions(+), 23 deletions(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index b96442960aea..dc3ca21ba240 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h

@@ -168,14 +168,6 @@
 #define IOREMAP_MAX_ORDER      (PMD_SHIFT)
 #endif

-#ifdef CONFIG_BLK_DEV_INITRD
-#define __early_init_dt_declare_initrd(__start, __end)                 \
-       do {                                                            \
-               initrd_start = (__start);                               \
-               initrd_end = (__end);                                   \
-       } while (0)
-#endif
-
 #ifndef __ASSEMBLY__

 #include <linux/bitops.h>

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 3cf87341859f..292570b08f85 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c

@@ -62,6 +62,8 @@
 s64 memstart_addr __ro_after_init = -1;
 phys_addr_t arm64_dma_phys_limit __ro_after_init;

+static phys_addr_t phys_initrd_start, phys_initrd_end;
+
 #ifdef CONFIG_BLK_DEV_INITRD
 static int __init early_initrd(char *p)
 {

@@ -72,8 +74,8 @@ static int __init early_initrd(char *p)
        if (*endp == ',') {
                size = memparse(endp + 1, NULL);

-               initrd_start = start;
-               initrd_end = start + size;
+               phys_initrd_start = start;
+               phys_initrd_end = start + size;
        }
        return 0;
 }

@@ -364,6 +366,7 @@ static void __init fdt_enforce_memory_region(void)
 void __init arm64_memblock_init(void)
 {
        const s64 linear_region_size = -(s64)PAGE_OFFSET;
+       u64 __maybe_unused base, size;

        /* Handle linux,usable-memory-range property */
        fdt_enforce_memory_region();

@@ -408,14 +411,25 @@ void __init arm64_memblock_init(void)
                memblock_add(__pa_symbol(_text), (u64)(_end - _text));
        }

-       if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && initrd_start) {
+       if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) &&
+           (initrd_start || phys_initrd_start)) {

I've tried to explain already that this is broken. The problem is
__early_init_dt_declare_initrd using __va() which happens before this
function is called. __va() uses PHYS_OFFSET which in turn is defined
as memstart_addr. However, memstart_addr may be changed just above
this hunk, so the earlier conversion to a VA may not be valid at this
point. This is explained if you read Ard's commit that added all this
mess.

Thanks for explaining this again, looks like I had overlooked that
explanation in the "other branch" of the thread last time I read it.

You could fix this by converting back to a PA before adjusting
memstart_addr, but that's 2 wrongs making a right and fragile. The
better solution is the other proposal making the DT code set
phys_initrd_* (whatever the ARM code calls them).

OK, that sounds reasonable, will cook something doing that. Thanks!

quoted

                /*
                 * Add back the memory we just removed if it results in the
                 * initrd to become inaccessible via the linear mapping.
                 * Otherwise, this is a no-op
                 */
-               u64 base = initrd_start & PAGE_MASK;
-               u64 size = PAGE_ALIGN(initrd_end) - base;
+               if (phys_initrd_start) {
+                       /* Command line specified the initrd location */
+                       initrd_start = __phys_to_virt(phys_initrd_start);
+                       initrd_end = __phys_to_virt(phys_initrd_end);
+               } else if (initrd_start) {
+                       /* FDT specified the initrd location */
+                       phys_initrd_start = __pa(initrd_start);
+                       phys_initrd_end = __pa(initrd_end);

Kind of inconsistent to mix __phys_to_virt and __pa flavors.

Rob

-- 
Florian