On Thu, Sep 23, 2021 at 03:54:46PM +0200, Christophe Leroy wrote:

Le 23/09/2021 à 14:01, Mike Rapoport a écrit :

quoted

On Thu, Sep 23, 2021 at 11:47:48AM +0200, Christophe Leroy wrote:

quoted

Le 23/09/2021 à 09:43, Mike Rapoport a écrit :

quoted

From: Mike Rapoport <redacted>

For ages memblock_free() interface dealt with physical addresses even
despite the existence of memblock_alloc_xx() functions that return a
virtual pointer.

Introduce memblock_phys_free() for freeing physical ranges and repurpose
memblock_free() to free virtual pointers to make the following pairing
abundantly clear:

	int memblock_phys_free(phys_addr_t base, phys_addr_t size);
	phys_addr_t memblock_phys_alloc(phys_addr_t base, phys_addr_t size);

	void *memblock_alloc(phys_addr_t size, phys_addr_t align);
	void memblock_free(void *ptr, size_t size);

Replace intermediate memblock_free_ptr() with memblock_free() and drop
unnecessary aliases memblock_free_early() and memblock_free_early_nid().

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mike Rapoport <redacted>
---

quoted

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 1a04e5bdf655..37826d8c4f74 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c

@@ -723,7 +723,7 @@ void __init smp_save_dump_cpus(void)
   			/* Get the CPU registers */
   			smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
   	}
-	memblock_free(page, PAGE_SIZE);
+	memblock_phys_free(page, PAGE_SIZE);
   	diag_amode31_ops.diag308_reset();
   	pcpu_set_smt(0);
   }

@@ -880,7 +880,7 @@ void __init smp_detect_cpus(void)
   	/* Add CPUs present at boot */
   	__smp_rescan_cpus(info, true);
-	memblock_free_early((unsigned long)info, sizeof(*info));
+	memblock_free(info, sizeof(*info));
   }
   /*

I'm a bit lost. IIUC memblock_free_early() and memblock_free() where
identical.

Yes, they were, but all calls to memblock_free_early() were using
__pa(vaddr) because they had a virtual address at hand.

I'm still not following. In the above memblock_free_early() was taking
(unsigned long)info . Was it a bug ? 

Not really because s390 has pa == va:

https://elixir.bootlin.com/linux/latest/source/arch/s390/include/asm/page.h#L169


-- 
Sincerely yours,
Mike.