Adding upstream version 4.19.304.upstream/4.19.304upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 20 insertions, 16 deletions

diff --git a/arch/parisc/include/asm/ldcw.h b/arch/parisc/include/asm/ldcw.h
index 3eb4bfc1f..5ed52819e 100644
--- a/arch/parisc/include/asm/ldcw.h
+++ b/arch/parisc/include/asm/ldcw.h
@@ -2,14 +2,28 @@
 #ifndef __PARISC_LDCW_H
 #define __PARISC_LDCW_H
 
-#ifndef CONFIG_PA20
 /* Because kmalloc only guarantees 8-byte alignment for kmalloc'd data,
    and GCC only guarantees 8-byte alignment for stack locals, we can't
    be assured of 16-byte alignment for atomic lock data even if we
    specify "__attribute ((aligned(16)))" in the type declaration.  So,
    we use a struct containing an array of four ints for the atomic lock
    type and dynamically select the 16-byte aligned int from the array
-   for the semaphore.  */
+   for the semaphore. */
+
+/* From: "Jim Hull" <jim.hull of hp.com>
+   I've attached a summary of the change, but basically, for PA 2.0, as
+   long as the ",CO" (coherent operation) completer is implemented, then the
+   16-byte alignment requirement for ldcw and ldcd is relaxed, and instead
+   they only require "natural" alignment (4-byte for ldcw, 8-byte for
+   ldcd).
+
+   Although the cache control hint is accepted by all PA 2.0 processors,
+   it is only implemented on PA8800/PA8900 CPUs. Prior PA8X00 CPUs still
+   require 16-byte alignment. If the address is unaligned, the operation
+   of the instruction is undefined. The ldcw instruction does not generate
+   unaligned data reference traps so misaligned accesses are not detected.
+   This hid the problem for years. So, restore the 16-byte alignment dropped
+   by Kyle McMartin in "Remove __ldcw_align for PA-RISC 2.0 processors". */
 
 #define __PA_LDCW_ALIGNMENT	16
 #define __PA_LDCW_ALIGN_ORDER	4
@@ -19,22 +33,12 @@
 		& ~(__PA_LDCW_ALIGNMENT - 1);			\
 	(volatile unsigned int *) __ret;			\
 })
-#define __LDCW	"ldcw"
 
-#else /*CONFIG_PA20*/
-/* From: "Jim Hull" <jim.hull of hp.com>
-   I've attached a summary of the change, but basically, for PA 2.0, as
-   long as the ",CO" (coherent operation) completer is specified, then the
-   16-byte alignment requirement for ldcw and ldcd is relaxed, and instead
-   they only require "natural" alignment (4-byte for ldcw, 8-byte for
-   ldcd). */
-
-#define __PA_LDCW_ALIGNMENT	4
-#define __PA_LDCW_ALIGN_ORDER	2
-#define __ldcw_align(a) (&(a)->slock)
+#ifdef CONFIG_PA20
 #define __LDCW	"ldcw,co"
-
-#endif /*!CONFIG_PA20*/
+#else
+#define __LDCW	"ldcw"
+#endif
 
 /* LDCW, the only atomic read-write operation PA-RISC has. *sigh*.
    We don't explicitly expose that "*a" may be written as reload