[Xen-devel] [PATCH 2/7] xen/arm: setup the fixmap in head.S

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Setup the fixmap mapping directly in head.S rather than having a
temporary mapping only to re-do it later in C.


Changes in v2:

- fix code style;
- more comments;
- always hook xen_fixmap in the pagetable but fill in the console fixmap
only if EARLY_UART_ADDRESS.


Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 xen/arch/arm/early_printk.c |    5 ++---
 xen/arch/arm/head.S         |   40 +++++++++++++++++++++++-----------------
 xen/arch/arm/mm.c           |    2 +-
 xen/arch/arm/setup.c        |    2 --
 4 files changed, 26 insertions(+), 23 deletions(-)

diff --git a/xen/arch/arm/early_printk.c b/xen/arch/arm/early_printk.c
index 3e51252..bdf4c0e 100644
--- a/xen/arch/arm/early_printk.c
+++ b/xen/arch/arm/early_printk.c
@@ -17,12 +17,11 @@
 
 #ifdef EARLY_UART_ADDRESS
 
-static void __init early_putch(char c)
+void __init early_putch(char c)
 {
     volatile uint32_t *r;
 
-    r = (uint32_t *)((EARLY_UART_ADDRESS & 0x001fffff)
-                     + XEN_VIRT_START + (1 << 21));
+    r = (uint32_t *)(XEN_VIRT_START + (1 << 21));
 
     /* XXX: assuming a PL011 UART. */
     while(*(r + 0x6) & 0x8)
diff --git a/xen/arch/arm/head.S b/xen/arch/arm/head.S
index 9fdeda7..4506244 100644
--- a/xen/arch/arm/head.S
+++ b/xen/arch/arm/head.S
@@ -24,6 +24,7 @@
 #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 */
 #define PT_DEV 0xe71 /* nG=1, AF=1, SH=10, AP=01, NS=1, ATTR=100, T=0, P=1 */
+#define PT_DEV_L3 0xe73 /* lev3: nG=1, AF=1, SH=10, AP=01, NS=1, ATTR=100, 
T=1, P=1 */
 
 #define PT_UPPER(x) (PT_##x & 0xf00)
 #define PT_LOWER(x) (PT_##x & 0x0ff)
@@ -183,6 +184,18 @@ skip_bss:
        teq   r12, #0
        bne   pt_ready
        
+       /* console fixmap */
+#ifdef EARLY_UART_ADDRESS
+       ldr   r1, =xen_fixmap
+       add   r1, r1, r10            /* r1 := paddr (xen_fixmap) */
+       mov   r3, #0
+       lsr   r2, r11, #12
+       lsl   r2, r2, #12            /* 4K aligned paddr of UART */
+       orr   r2, r2, #PT_UPPER(DEV_L3)
+       orr   r2, r2, #PT_LOWER(DEV_L3) /* r2:r3 := 4K dev map including UART */
+       strd  r2, r3, [r1, #(FIXMAP_CONSOLE*8)] /* Map it in the first fixmap's 
slot */
+#endif
+       
        /* Build the baseline idle pagetable's first-level entries */
        ldr   r1, =xen_second
        add   r1, r1, r10            /* r1 := paddr (xen_second) */
@@ -205,17 +218,15 @@ skip_bss:
        ldr   r4, =start
        lsr   r4, #18                /* Slot for vaddr(start) */
        strd  r2, r3, [r1, r4]       /* Map Xen there too */
-#ifdef EARLY_UART_ADDRESS
-       ldr   r3, =(1<<(54-32))      /* NS for device mapping */
-       lsr   r2, r11, #21
-       lsl   r2, r2, #21            /* 2MB-aligned paddr of UART */
-       orr   r2, r2, #PT_UPPER(DEV)
-       orr   r2, r2, #PT_LOWER(DEV) /* r2:r3 := 2MB dev map including UART */
+
+       /* xen_fixmap pagetable */
+       ldr   r2, =xen_fixmap
+       add   r2, r2, r10            /* r2 := paddr (xen_fixmap) */
+       orr   r2, r2, #PT_UPPER(PT)
+       orr   r2, r2, #PT_LOWER(PT)  /* r2:r3 := table map of xen_fixmap */
        add   r4, r4, #8
        strd  r2, r3, [r1, r4]       /* Map it in the fixmap's slot */
-#else
-       add   r4, r4, #8             /* Skip over unused fixmap slot */
-#endif
+
        mov   r3, #0x0
        lsr   r2, r8, #21
        lsl   r2, r2, #21            /* 2MB-aligned paddr of DTB */
@@ -236,13 +247,10 @@ pt_ready:
        mov   pc, r1                 /* Get a proper vaddr into PC */
 paging:
 
+       
 #ifdef EARLY_UART_ADDRESS
-       /* Recover the UART address in the new address space. */
-       lsl   r11, #11
-       lsr   r11, #11               /* UART base's offset from 2MB base */
-       adr   r0, start
-       add   r0, r0, #0x200000      /* vaddr of the fixmap's 2MB slot */
-       add   r11, r11, r0           /* r11 := vaddr (UART base address) */
+    /* Use a virtual address to access the UART. */
+       ldr   r11, =FIXMAP_ADDR(FIXMAP_CONSOLE)
 #endif
 
        PRINT("- Ready -\r\n")
@@ -261,8 +269,6 @@ paging:
        mcr   CP32(r0, BPIALL)       /* Flush branch predictor */
        dsb                          /* Ensure completion of TLB+BP flush */
        isb
-       /* Now, the UART is in its proper fixmap address */
-       ldrne r11, =FIXMAP_ADDR(FIXMAP_CONSOLE)
 
        /* Non-boot CPUs report that they've got this far */
        ldr   r0, =ready_cpus
diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index b0068d2..d0cd2c9 100644
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -37,7 +37,7 @@ struct domain *dom_xen, *dom_io;
 /* Static start-of-day pagetables that we use before the allocators are up */
 lpae_t xen_pgtable[LPAE_ENTRIES] __attribute__((__aligned__(4096)));
 lpae_t xen_second[LPAE_ENTRIES*4] __attribute__((__aligned__(4096*4)));
-static lpae_t xen_fixmap[LPAE_ENTRIES] __attribute__((__aligned__(4096)));
+lpae_t xen_fixmap[LPAE_ENTRIES] __attribute__((__aligned__(4096)));
 static lpae_t xen_xenmap[LPAE_ENTRIES] __attribute__((__aligned__(4096)));
 
 /* Non-boot CPUs use this to find the correct pagetables. */
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 7568968..6fbcb81 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -194,9 +194,7 @@ void __init start_xen(unsigned long boot_phys_offset,
     setup_pagetables(boot_phys_offset, get_xen_paddr());
 
 #ifdef EARLY_UART_ADDRESS
-    /* Map the UART */
     /* TODO Need to get device tree or command line for UART address */
-    set_fixmap(FIXMAP_CONSOLE, EARLY_UART_ADDRESS >> PAGE_SHIFT, DEV_SHARED);
     pl011_init(0, FIXMAP_ADDR(FIXMAP_CONSOLE));
     console_init_preirq();
 #endif
-- 
1.7.2.5


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