git: e79989d8233b - stable/13 - LinuxKPI: Add more #ifdef VM_MEMATTR_WRITE_COMBINING guards

The branch stable/13 has been updated by jrtc27:

URL: https://cgit.FreeBSD.org/src/commit/?id=e79989d8233bf4732a5a1d904e3de7c67d8220cd

commit e79989d8233bf4732a5a1d904e3de7c67d8220cd
Author:     Jessica Clarke <jrtc27@FreeBSD.org>
AuthorDate: 2021-10-03 18:34:40 +0000
Commit:     Jessica Clarke <jrtc27@FreeBSD.org>
CommitDate: 2021-10-10 13:36:53 +0000

    LinuxKPI: Add more #ifdef VM_MEMATTR_WRITE_COMBINING guards
    
    One of the three uses is already guarded; this guards the remaining ones
    to support architectures like riscv that do not provide write-combining,
    and is needed to build drm-kmod on riscv.
    
    Reviewed by:    hselasky, manu
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D31999
    
    (cherry picked from commit 8167c92f65bc20145467b3b98c842cde57736900)
---
 sys/compat/linuxkpi/common/include/linux/io.h   | 4 ++++
 sys/compat/linuxkpi/common/include/linux/page.h | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/sys/compat/linuxkpi/common/include/linux/io.h b/sys/compat/linuxkpi/common/include/linux/io.h
index 0104eea90ace..074417b892f9 100644
--- a/sys/compat/linuxkpi/common/include/linux/io.h
+++ b/sys/compat/linuxkpi/common/include/linux/io.h
@@ -411,8 +411,12 @@ void *_ioremap_attr(vm_paddr_t phys_addr, unsigned long size, int attr);
 #define	ioremap(addr, size)						\
     _ioremap_attr((addr), (size), VM_MEMATTR_UNCACHEABLE)
 #endif
+#ifdef VM_MEMATTR_WRITE_COMBINING
 #define	ioremap_wc(addr, size)						\
     _ioremap_attr((addr), (size), VM_MEMATTR_WRITE_COMBINING)
+#else
+#define	ioremap_wc(addr, size)	ioremap_nocache(addr, size)
+#endif
 #define	ioremap_wb(addr, size)						\
     _ioremap_attr((addr), (size), VM_MEMATTR_WRITE_BACK)
 void iounmap(void *addr);
diff --git a/sys/compat/linuxkpi/common/include/linux/page.h b/sys/compat/linuxkpi/common/include/linux/page.h
index c2dbab769c2a..a09ae439266e 100644
--- a/sys/compat/linuxkpi/common/include/linux/page.h
+++ b/sys/compat/linuxkpi/common/include/linux/page.h
@@ -76,8 +76,12 @@ pgprot2cachemode(pgprot_t prot)
 #define	clear_page(page)		memset(page, 0, PAGE_SIZE)
 #define	pgprot_noncached(prot)		\
 	(((prot) & VM_PROT_ALL) | cachemode2protval(VM_MEMATTR_UNCACHEABLE))
+#ifdef VM_MEMATTR_WRITE_COMBINING
 #define	pgprot_writecombine(prot)	\
 	(((prot) & VM_PROT_ALL) | cachemode2protval(VM_MEMATTR_WRITE_COMBINING))
+#else
+#define	pgprot_writecombine(prot)	pgprot_noncached(prot)
+#endif
 
 #undef	PAGE_MASK
 #define	PAGE_MASK	(~(PAGE_SIZE-1))