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Re: [Xen-devel] [PATCH V2] xen/arm: UART addresses are not always aligned to a page.

From: Ian Campbell <Ian.Campbell@xxxxxxxxxx>

Date: Thu, 31 Oct 2013 16:27:22 +0000

Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, julien.grall@xxxxxxxxxx, tim@xxxxxxx, xen-devel@xxxxxxxxxxxxx

Delivery-date: Thu, 31 Oct 2013 16:27:59 +0000

List-id: Xen developer discussion <xen-devel.lists.xen.org>

On Wed, 2013-10-30 at 18:53 -0400, Jon Fraser wrote: > On Wed, 2013-10-30 at 21:25 +0000, Andrew Cooper wrote: > > On 30/10/13 21:18, Jon Fraser wrote: > > > When calculating the virtual address of the UART, > > > add the page offset of the UART to the mapped address. > > > > > > Create define EARLY_UART_VIRTUAL_ADDRESS and use instead > > > of FIXMAP_ADDR(FIXMAP_CONSOLE) > > > > > > Signed-off-by: Jon Fraser <jfraser@xxxxxxxxxxxx> > > > --- > > > xen/arch/arm/arm32/debug.S | 5 +++-- > > > xen/arch/arm/arm32/head.S | 3 ++- > > > xen/arch/arm/arm64/debug.S | 5 +++-- > > > xen/arch/arm/arm64/head.S | 3 ++- > > > xen/include/asm-arm/early_printk.h | 10 ++++++++++ > > > 5 files changed, 20 insertions(+), 6 deletions(-) > > > > > > diff --git a/xen/arch/arm/arm32/debug.S b/xen/arch/arm/arm32/debug.S > > > index ec774cd..a95d9da 100644 > > > --- a/xen/arch/arm/arm32/debug.S > > > +++ b/xen/arch/arm/arm32/debug.S > > > @@ -18,6 +18,7 @@ > > > */ > > > > > > #include <asm/config.h> > > > +#include <asm/early_printk.h> > > > > > > #ifdef EARLY_PRINTK_INC > > > #include EARLY_PRINTK_INC > > > @@ -26,14 +27,14 @@ > > > /* Print a character on the UART - this function is called by C > > > * r0: character to print */ > > > GLOBAL(early_putch) > > > - ldr r1, =FIXMAP_ADDR(FIXMAP_CONSOLE) /* r1 := VA UART base > > > address */ > > > + ldr r1, =EARLY_UART_VIRTUAL_ADDRESS /* r1 := VA UART base > > > address */ > > > early_uart_ready r1, r2 > > > early_uart_transmit r1, r0 > > > mov pc, lr > > > > > > /* Flush the UART - this function is called by C */ > > > GLOBAL(early_flush) > > > - ldr r1, =FIXMAP_ADDR(FIXMAP_CONSOLE) /* r1 := VA UART base > > > address */ > > > + ldr r1, =EARLY_UART_VIRTUAL_ADDRESS /* r1 := VA UART base > > > address */ > > > early_uart_ready r1, r2 > > > mov pc, lr > > > > > > diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S > > > index ce1d21a..96230ac 100644 > > > --- a/xen/arch/arm/arm32/head.S > > > +++ b/xen/arch/arm/arm32/head.S > > > @@ -22,6 +22,7 @@ > > > #include <asm/processor-ca15.h> > > > #include <asm/processor-ca7.h> > > > #include <asm/asm_defns.h> > > > +#include <asm/early_printk.h> > > > > > > #define ZIMAGE_MAGIC_NUMBER 0x016f2818 > > > > > > @@ -356,7 +357,7 @@ paging: > > > strd r2, r3, [r1, r4] /* Map it in the fixmap's slot */ > > > > > > /* Use a virtual address to access the UART. */ > > > - ldr r11, =FIXMAP_ADDR(FIXMAP_CONSOLE) > > > + ldr r11, =EARLY_UART_VIRTUAL_ADDRESS > > > #endif > > > /* Map the DTB in the boot misc slot */ > > > teq r12, #0 /* Only on boot CPU */ > > > diff --git a/xen/arch/arm/arm64/debug.S b/xen/arch/arm/arm64/debug.S > > > index 472c157..a855358 100644 > > > --- a/xen/arch/arm/arm64/debug.S > > > +++ b/xen/arch/arm/arm64/debug.S > > > @@ -18,6 +18,7 @@ > > > */ > > > > > > #include <asm/config.h> > > > +#include <asm/early_printk.h> > > > > > > #ifdef EARLY_PRINTK_INC > > > #include EARLY_PRINTK_INC > > > @@ -26,14 +27,14 @@ > > > /* Print a character on the UART - this function is called by C > > > * x0: character to print */ > > > GLOBAL(early_putch) > > > - ldr x15, =FIXMAP_ADDR(FIXMAP_CONSOLE) > > > + ldr x15, =EARLY_UART_VIRTUAL_ADDRESS > > > early_uart_ready x15, 1 > > > early_uart_transmit x15, w0 > > > ret > > > > > > /* Flush the UART - this function is called by C */ > > > GLOBAL(early_flush) > > > - ldr x15, =FIXMAP_ADDR(FIXMAP_CONSOLE) /* x15 := VA UART base > > > address */ > > > + ldr x15, =EARLY_UART_VIRTUAL_ADDRESS /* x15 := VA UART base > > > address */ > > > early_uart_ready x15, 1 > > > ret > > > > > > diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S > > > index b8b5902..31afdd0 100644 > > > --- a/xen/arch/arm/arm64/head.S > > > +++ b/xen/arch/arm/arm64/head.S > > > @@ -23,6 +23,7 @@ > > > #include <asm/config.h> > > > #include <asm/page.h> > > > #include <asm/asm_defns.h> > > > +#include <asm/early_printk.h> > > > > > > #define PT_PT 0xe7f /* nG=1 AF=1 SH=10 AP=01 NS=1 ATTR=111 T=1 P=1 */ > > > #define PT_MEM 0xe7d /* nG=1 AF=1 SH=10 AP=01 NS=1 ATTR=111 T=0 P=1 */ > > > @@ -368,7 +369,7 @@ paging: > > > str x2, [x4, x1] /* Map it in the fixmap's slot */ > > > > > > /* Use a virtual address to access the UART. */ > > > - ldr x23, =FIXMAP_ADDR(FIXMAP_CONSOLE) > > > + ldr x23, =EARLY_UART_VIRTUAL_ADDRESS > > > #endif > > > > > > /* Map the DTB in the boot misc slot */ > > > diff --git a/xen/include/asm-arm/early_printk.h > > > b/xen/include/asm-arm/early_printk.h > > > index 5f7c529..759d59a 100644 > > > --- a/xen/include/asm-arm/early_printk.h > > > +++ b/xen/include/asm-arm/early_printk.h > > > @@ -12,6 +12,14 @@ > > > > > > #include <xen/config.h> > > > > > > +#ifdef __ASSEMBLY__ > > > + > > > +/* need to add the uart address offset in page to the fixmap address */ > > > +#define EARLY_UART_VIRTUAL_ADDRESS \ > > > + (FIXMAP_ADDR(FIXMAP_CONSOLE) +(EARLY_UART_BASE_ADDRESS & ~PAGE_MASK)) > > > > Why should this be limited to assembly code? It would seem valid for > > early C code to see and use as well. > > > > With that change, you can drop all the #ifdef'ary > > > > ~Andrew > > > > The problem is that the C code in the include can't be included in the > assembler files. I suppose that EARLY_UART_VIRTUAL_ADDRESS could be > used in C code. C code should be using early_printk, not anything which would need to touch EARLY_UART_VIRTUAL_ADDRESS. Ultimately early_printk uses early_putch which is implemented in ASM and is where EARLY_UART_VIRTUAL_ADDRESS should be used (and I suppose is by this patch, I didn't check). (this doesn't mean the #define should be hidden from C, just that it shouldn't be used). I think your __ASSEMBLY__ #ifdef is ok, but shouldn't it be inside the #idef EARLY_PRINTK? > I'd still have to ifdef out the C code in the include > file for the assembler files. #ifndef __ASSEMBLY__ and drop the #else if you like, so C sees everything and ASM sees only the relevant define that would be fine too. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel

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