From: Niklas Schnelle Date: Fri, 21 Feb 2025 11:51:48 +0000 (+0100) Subject: s390: Remove ioremap_wt() and pgprot_writethrough() X-Git-Tag: v6.15-rc1~113^2~17 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c94bff63e49302d4ce36502a85a2710a67332a4f;p=thirdparty%2Fkernel%2Flinux.git s390: Remove ioremap_wt() and pgprot_writethrough() It turns out that while s390 architecture calls its memory-I/O mapping variants write-through and write-back the implementation of ioremap_wt() and pgprot_writethrough() does not match Linux notion of ioremap_wt(). In particular Linux expects ioremap_wt() to be weaker still than ioremap_wc(), allowing not just gathering and re-ordering but also reads to be served from cache. Instead s390's implementation is equivalent to normal ioremap() while its ioremap_wc() allows re-ordering. Note that there are no known users of ioremap_wt() on s390 and the resulting behavior is in line with asm-generic defining ioremap_wt() as ioremap(), if undefined, so no breakage is expected. As s390 does not have a mapping type matching the Linux notion of ioremap_wt() and pgprot_writethrough(), simply drop them and rely on the asm-generic fallbacks instead. Fixes: b02002cc4c0f ("s390/pci: Implement ioremap_wc/prot() with MIO") Fixes: b43b3fff042d ("s390: mm: convert to GENERIC_IOREMAP") Acked-by: Heiko Carstens Signed-off-by: Niklas Schnelle Signed-off-by: Vasily Gorbik --- diff --git a/arch/s390/include/asm/io.h b/arch/s390/include/asm/io.h index fc9933a743d69..251e0372ccbd0 100644 --- a/arch/s390/include/asm/io.h +++ b/arch/s390/include/asm/io.h @@ -34,8 +34,6 @@ void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr); #define ioremap_wc(addr, size) \ ioremap_prot((addr), (size), pgprot_val(pgprot_writecombine(PAGE_KERNEL))) -#define ioremap_wt(addr, size) \ - ioremap_prot((addr), (size), pgprot_val(pgprot_writethrough(PAGE_KERNEL))) static inline void __iomem *ioport_map(unsigned long port, unsigned int nr) { diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index fb757f5e220b0..e9c2d81f11f83 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1403,9 +1403,6 @@ void gmap_pmdp_idte_global(struct mm_struct *mm, unsigned long vmaddr); #define pgprot_writecombine pgprot_writecombine pgprot_t pgprot_writecombine(pgprot_t prot); -#define pgprot_writethrough pgprot_writethrough -pgprot_t pgprot_writethrough(pgprot_t prot); - #define PFN_PTE_SHIFT PAGE_SHIFT /* diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index e20fd4c14562c..fa66246c18513 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -36,16 +36,6 @@ pgprot_t pgprot_writecombine(pgprot_t prot) } EXPORT_SYMBOL_GPL(pgprot_writecombine); -pgprot_t pgprot_writethrough(pgprot_t prot) -{ - /* - * mio_wb_bit_mask may be set on a different CPU, but it is only set - * once at init and only read afterwards. - */ - return __pgprot(pgprot_val(prot) & ~mio_wb_bit_mask); -} -EXPORT_SYMBOL_GPL(pgprot_writethrough); - static inline void ptep_ipte_local(struct mm_struct *mm, unsigned long addr, pte_t *ptep, int nodat) {