| Message ID | 1377080143-28455-6-git-send-email-tangchen@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
Tang Chen <tangchen@cn.fujitsu.com> wrote: >We are going to do acpi_initrd_override() at very early time: > >On 32bit: do it in head_32.S, before paging is enabled. In this case, >we can > access initrd with physical address without page tables. > >On 64bit: do it in head_64.c, after paging is enabled but before direct >mapping > is setup. > > On 64bit, we have an early page fault handler to help to access data > with direct mapping page tables. So it is easy to do in head_64.c. > >And we need to allocate memory to store override tables. At such an >early time, >no memory allocator works. So we can only use BRK. > >As mentioned above, on 32bit before paging is enabled, we have to >access variables >with pa. So introduce a "bool is_phys" parameter to extend_brk(), and >convert va >to pa is it is true. Could you do it differently? Meaning have a global symbol (paging_enabled) which will be used by most of the functions you changed in this patch and the next ones? It would naturally be enabled when paging is on and __va addresses can be used. That could also be used in the printk case to do a BUG_ON before paging is enabled on 32bit. Or perhaps use a different code path to deal with using __pa address. ? > >Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com> >--- > arch/x86/include/asm/dmi.h | 2 +- > arch/x86/include/asm/setup.h | 2 +- > arch/x86/kernel/setup.c | 20 ++++++++++++++------ > arch/x86/mm/init.c | 2 +- > arch/x86/xen/enlighten.c | 2 +- > arch/x86/xen/mmu.c | 6 +++--- > arch/x86/xen/p2m.c | 27 ++++++++++++++------------- > drivers/acpi/osl.c | 2 +- > 8 files changed, 36 insertions(+), 27 deletions(-) > >diff --git a/arch/x86/include/asm/dmi.h b/arch/x86/include/asm/dmi.h >index fd8f9e2..3b51d81 100644 >--- a/arch/x86/include/asm/dmi.h >+++ b/arch/x86/include/asm/dmi.h >@@ -9,7 +9,7 @@ > > static __always_inline __init void *dmi_alloc(unsigned len) > { >- return extend_brk(len, sizeof(int)); >+ return extend_brk(len, sizeof(int), false); > } > > /* Use early IO mappings for DMI because it's initialized early */ >diff --git a/arch/x86/include/asm/setup.h >b/arch/x86/include/asm/setup.h >index 4f71d48..96d00da 100644 >--- a/arch/x86/include/asm/setup.h >+++ b/arch/x86/include/asm/setup.h >@@ -75,7 +75,7 @@ extern struct boot_params boot_params; > > /* exceedingly early brk-like allocator */ > extern unsigned long _brk_end; >-void *extend_brk(size_t size, size_t align); >+void *extend_brk(size_t size, size_t align, bool is_phys); > > /* > * Reserve space in the brk section. The name must be unique within >diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c >index 51fcd5d..a189909 100644 >--- a/arch/x86/kernel/setup.c >+++ b/arch/x86/kernel/setup.c >@@ -259,19 +259,27 @@ static inline void __init copy_edd(void) > } > #endif > >-void * __init extend_brk(size_t size, size_t align) >+void * __init extend_brk(size_t size, size_t align, bool is_phys) > { > size_t mask = align - 1; > void *ret; >+ unsigned long *brk_start, *brk_end, *brk_limit; > >- BUG_ON(_brk_start == 0); >+ brk_start = is_phys ? (unsigned long *)__pa_nodebug(&_brk_start) : >+ (unsigned long *)&_brk_start; >+ brk_end = is_phys ? (unsigned long *)__pa_nodebug(&_brk_end) : >+ (unsigned long *)&_brk_end; >+ brk_limit = is_phys ? (unsigned long *)__pa_nodebug(__brk_limit) : >+ (unsigned long *)__brk_limit; >+ >+ BUG_ON(*brk_start == 0); > BUG_ON(align & mask); > >- _brk_end = (_brk_end + mask) & ~mask; >- BUG_ON((char *)(_brk_end + size) > __brk_limit); >+ *brk_end = (*brk_end + mask) & ~mask; >+ BUG_ON((char *)(*brk_end + size) > brk_limit); > >- ret = (void *)_brk_end; >- _brk_end += size; >+ ret = (void *)(*brk_end); >+ *brk_end += size; > > memset(ret, 0, size); > >diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c >index 2ec29ac..189a9e2 100644 >--- a/arch/x86/mm/init.c >+++ b/arch/x86/mm/init.c >@@ -86,7 +86,7 @@ void __init early_alloc_pgt_buf(void) > unsigned long tables = INIT_PGT_BUF_SIZE; > phys_addr_t base; > >- base = __pa(extend_brk(tables, PAGE_SIZE)); >+ base = __pa(extend_brk(tables, PAGE_SIZE, false)); > > pgt_buf_start = base >> PAGE_SHIFT; > pgt_buf_end = pgt_buf_start; >diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c >index 193097e..2d5a34f 100644 >--- a/arch/x86/xen/enlighten.c >+++ b/arch/x86/xen/enlighten.c >@@ -1629,7 +1629,7 @@ void __ref xen_hvm_init_shared_info(void) > > if (!shared_info_page) > shared_info_page = (struct shared_info *) >- extend_brk(PAGE_SIZE, PAGE_SIZE); >+ extend_brk(PAGE_SIZE, PAGE_SIZE, false); > xatp.domid = DOMID_SELF; > xatp.idx = 0; > xatp.space = XENMAPSPACE_shared_info; >diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c >index fdc3ba2..573bc50 100644 >--- a/arch/x86/xen/mmu.c >+++ b/arch/x86/xen/mmu.c >@@ -1768,7 +1768,7 @@ static void __init xen_map_identity_early(pmd_t >*pmd, unsigned long max_pfn) > unsigned long pfn; > > level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES, >- PAGE_SIZE); >+ PAGE_SIZE, false); > > ident_pte = 0; > pfn = 0; >@@ -1980,7 +1980,7 @@ static void __init xen_write_cr3_init(unsigned >long cr3) > * swapper_pg_dir. > */ > swapper_kernel_pmd = >- extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE); >+ extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE, false); > copy_page(swapper_kernel_pmd, initial_kernel_pmd); > swapper_pg_dir[KERNEL_PGD_BOUNDARY] = > __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT); >@@ -2003,7 +2003,7 @@ void __init xen_setup_kernel_pagetable(pgd_t >*pgd, unsigned long max_pfn) > pmd_t *kernel_pmd; > > initial_kernel_pmd = >- extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE); >+ extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE, false); > > max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) + > xen_start_info->nr_pt_frames * PAGE_SIZE + >diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c >index 95fb2aa..bbdcf20 100644 >--- a/arch/x86/xen/p2m.c >+++ b/arch/x86/xen/p2m.c >@@ -281,13 +281,13 @@ void __ref xen_build_mfn_list_list(void) > > /* Pre-initialize p2m_top_mfn to be completely missing */ > if (p2m_top_mfn == NULL) { >- p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE, false); > p2m_mid_mfn_init(p2m_mid_missing_mfn); > >- p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE, false); > p2m_top_mfn_p_init(p2m_top_mfn_p); > >- p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE, false); > p2m_top_mfn_init(p2m_top_mfn); > } else { > /* Reinitialise, mfn's all change after migration */ >@@ -322,7 +322,7 @@ void __ref xen_build_mfn_list_list(void) > * runtime. extend_brk() will BUG if we call > * it too late. > */ >- mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE, false); > p2m_mid_mfn_init(mid_mfn_p); > > p2m_top_mfn_p[topidx] = mid_mfn_p; >@@ -351,16 +351,16 @@ void __init >xen_build_dynamic_phys_to_machine(void) > > xen_max_p2m_pfn = max_pfn; > >- p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE, false); > p2m_init(p2m_missing); > >- p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE, false); > p2m_mid_init(p2m_mid_missing); > >- p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE, false); > p2m_top_init(p2m_top); > >- p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE, false); > p2m_init(p2m_identity); > > /* >@@ -373,7 +373,8 @@ void __init xen_build_dynamic_phys_to_machine(void) > unsigned mididx = p2m_mid_index(pfn); > > if (p2m_top[topidx] == p2m_mid_missing) { >- unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE, >+ false); > p2m_mid_init(mid); > > p2m_top[topidx] = mid; >@@ -609,7 +610,7 @@ static bool __init early_alloc_p2m_middle(unsigned >long pfn, bool check_boundary > return false; > > /* Boundary cross-over for the edges: */ >- p2m = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ p2m = extend_brk(PAGE_SIZE, PAGE_SIZE, false); > > p2m_init(p2m); > >@@ -635,7 +636,7 @@ static bool __init early_alloc_p2m(unsigned long >pfn) > mid = p2m_top[topidx]; > mid_mfn_p = p2m_top_mfn_p[topidx]; > if (mid == p2m_mid_missing) { >- mid = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ mid = extend_brk(PAGE_SIZE, PAGE_SIZE, false); > > p2m_mid_init(mid); > >@@ -645,7 +646,7 @@ static bool __init early_alloc_p2m(unsigned long >pfn) > } > /* And the save/restore P2M tables.. */ > if (mid_mfn_p == p2m_mid_missing_mfn) { >- mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); >+ mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE, false); > p2m_mid_mfn_init(mid_mfn_p); > > p2m_top_mfn_p[topidx] = mid_mfn_p; >@@ -858,7 +859,7 @@ static void __init m2p_override_init(void) > unsigned i; > > m2p_overrides = extend_brk(sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH, >- sizeof(unsigned long)); >+ sizeof(unsigned long), false); > > for (i = 0; i < M2P_OVERRIDE_HASH; i++) > INIT_LIST_HEAD(&m2p_overrides[i]); >diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c >index 4c1baa7..dff7fcc 100644 >--- a/drivers/acpi/osl.c >+++ b/drivers/acpi/osl.c >@@ -563,7 +563,7 @@ RESERVE_BRK(acpi_override_tables_alloc, >ACPI_OVERRIDE_TABLES_SIZE); > void __init early_alloc_acpi_override_tables_buf(void) > { > acpi_tables_addr = __pa(extend_brk(ACPI_OVERRIDE_TABLES_SIZE, >- PAGE_SIZE)); >+ PAGE_SIZE, false)); > } > > void __init acpi_initrd_override(void *data, size_t size) -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Global symbols are inaccessible in physical mode. This is incidentally yet another example of "PV/weird platform violence", since in their absence it would be trivial to work around this by using segmentation. Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote: >Tang Chen <tangchen@cn.fujitsu.com> wrote: >>We are going to do acpi_initrd_override() at very early time: >> >>On 32bit: do it in head_32.S, before paging is enabled. In this case, >>we can >> access initrd with physical address without page tables. >> >>On 64bit: do it in head_64.c, after paging is enabled but before >direct >>mapping >> is setup. >> >> On 64bit, we have an early page fault handler to help to access >data >> with direct mapping page tables. So it is easy to do in >head_64.c. >> >>And we need to allocate memory to store override tables. At such an >>early time, >>no memory allocator works. So we can only use BRK. >> >>As mentioned above, on 32bit before paging is enabled, we have to >>access variables >>with pa. So introduce a "bool is_phys" parameter to extend_brk(), and >>convert va >>to pa is it is true. > >Could you do it differently? Meaning have a global symbol >(paging_enabled) which will be used by most of the functions you >changed in this patch and the next ones? It would naturally be enabled >when paging is on and __va addresses can be used. > >That could also be used in the printk case to do a BUG_ON before paging >is enabled on 32bit. Or perhaps use a different code path to deal with >using __pa address. > >? >> >>Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com> >>--- >> arch/x86/include/asm/dmi.h | 2 +- >> arch/x86/include/asm/setup.h | 2 +- >> arch/x86/kernel/setup.c | 20 ++++++++++++++------ >> arch/x86/mm/init.c | 2 +- >> arch/x86/xen/enlighten.c | 2 +- >> arch/x86/xen/mmu.c | 6 +++--- >> arch/x86/xen/p2m.c | 27 ++++++++++++++------------- >> drivers/acpi/osl.c | 2 +- >> 8 files changed, 36 insertions(+), 27 deletions(-) >> >>diff --git a/arch/x86/include/asm/dmi.h b/arch/x86/include/asm/dmi.h >>index fd8f9e2..3b51d81 100644 >>--- a/arch/x86/include/asm/dmi.h >>+++ b/arch/x86/include/asm/dmi.h >>@@ -9,7 +9,7 @@ >> >> static __always_inline __init void *dmi_alloc(unsigned len) >> { >>- return extend_brk(len, sizeof(int)); >>+ return extend_brk(len, sizeof(int), false); >> } >> >> /* Use early IO mappings for DMI because it's initialized early */ >>diff --git a/arch/x86/include/asm/setup.h >>b/arch/x86/include/asm/setup.h >>index 4f71d48..96d00da 100644 >>--- a/arch/x86/include/asm/setup.h >>+++ b/arch/x86/include/asm/setup.h >>@@ -75,7 +75,7 @@ extern struct boot_params boot_params; >> >> /* exceedingly early brk-like allocator */ >> extern unsigned long _brk_end; >>-void *extend_brk(size_t size, size_t align); >>+void *extend_brk(size_t size, size_t align, bool is_phys); >> >> /* >> * Reserve space in the brk section. The name must be unique within >>diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c >>index 51fcd5d..a189909 100644 >>--- a/arch/x86/kernel/setup.c >>+++ b/arch/x86/kernel/setup.c >>@@ -259,19 +259,27 @@ static inline void __init copy_edd(void) >> } >> #endif >> >>-void * __init extend_brk(size_t size, size_t align) >>+void * __init extend_brk(size_t size, size_t align, bool is_phys) >> { >> size_t mask = align - 1; >> void *ret; >>+ unsigned long *brk_start, *brk_end, *brk_limit; >> >>- BUG_ON(_brk_start == 0); >>+ brk_start = is_phys ? (unsigned long *)__pa_nodebug(&_brk_start) : >>+ (unsigned long *)&_brk_start; >>+ brk_end = is_phys ? (unsigned long *)__pa_nodebug(&_brk_end) : >>+ (unsigned long *)&_brk_end; >>+ brk_limit = is_phys ? (unsigned long *)__pa_nodebug(__brk_limit) : >>+ (unsigned long *)__brk_limit; >>+ >>+ BUG_ON(*brk_start == 0); >> BUG_ON(align & mask); >> >>- _brk_end = (_brk_end + mask) & ~mask; >>- BUG_ON((char *)(_brk_end + size) > __brk_limit); >>+ *brk_end = (*brk_end + mask) & ~mask; >>+ BUG_ON((char *)(*brk_end + size) > brk_limit); >> >>- ret = (void *)_brk_end; >>- _brk_end += size; >>+ ret = (void *)(*brk_end); >>+ *brk_end += size; >> >> memset(ret, 0, size); >> >>diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c >>index 2ec29ac..189a9e2 100644 >>--- a/arch/x86/mm/init.c >>+++ b/arch/x86/mm/init.c >>@@ -86,7 +86,7 @@ void __init early_alloc_pgt_buf(void) >> unsigned long tables = INIT_PGT_BUF_SIZE; >> phys_addr_t base; >> >>- base = __pa(extend_brk(tables, PAGE_SIZE)); >>+ base = __pa(extend_brk(tables, PAGE_SIZE, false)); >> >> pgt_buf_start = base >> PAGE_SHIFT; >> pgt_buf_end = pgt_buf_start; >>diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c >>index 193097e..2d5a34f 100644 >>--- a/arch/x86/xen/enlighten.c >>+++ b/arch/x86/xen/enlighten.c >>@@ -1629,7 +1629,7 @@ void __ref xen_hvm_init_shared_info(void) >> >> if (!shared_info_page) >> shared_info_page = (struct shared_info *) >>- extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> xatp.domid = DOMID_SELF; >> xatp.idx = 0; >> xatp.space = XENMAPSPACE_shared_info; >>diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c >>index fdc3ba2..573bc50 100644 >>--- a/arch/x86/xen/mmu.c >>+++ b/arch/x86/xen/mmu.c >>@@ -1768,7 +1768,7 @@ static void __init xen_map_identity_early(pmd_t >>*pmd, unsigned long max_pfn) >> unsigned long pfn; >> >> level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES, >>- PAGE_SIZE); >>+ PAGE_SIZE, false); >> >> ident_pte = 0; >> pfn = 0; >>@@ -1980,7 +1980,7 @@ static void __init xen_write_cr3_init(unsigned >>long cr3) >> * swapper_pg_dir. >> */ >> swapper_kernel_pmd = >>- extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE); >>+ extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE, false); >> copy_page(swapper_kernel_pmd, initial_kernel_pmd); >> swapper_pg_dir[KERNEL_PGD_BOUNDARY] = >> __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT); >>@@ -2003,7 +2003,7 @@ void __init xen_setup_kernel_pagetable(pgd_t >>*pgd, unsigned long max_pfn) >> pmd_t *kernel_pmd; >> >> initial_kernel_pmd = >>- extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE); >>+ extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE, false); >> >> max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) + >> xen_start_info->nr_pt_frames * PAGE_SIZE + >>diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c >>index 95fb2aa..bbdcf20 100644 >>--- a/arch/x86/xen/p2m.c >>+++ b/arch/x86/xen/p2m.c >>@@ -281,13 +281,13 @@ void __ref xen_build_mfn_list_list(void) >> >> /* Pre-initialize p2m_top_mfn to be completely missing */ >> if (p2m_top_mfn == NULL) { >>- p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> p2m_mid_mfn_init(p2m_mid_missing_mfn); >> >>- p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> p2m_top_mfn_p_init(p2m_top_mfn_p); >> >>- p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> p2m_top_mfn_init(p2m_top_mfn); >> } else { >> /* Reinitialise, mfn's all change after migration */ >>@@ -322,7 +322,7 @@ void __ref xen_build_mfn_list_list(void) >> * runtime. extend_brk() will BUG if we call >> * it too late. >> */ >>- mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> p2m_mid_mfn_init(mid_mfn_p); >> >> p2m_top_mfn_p[topidx] = mid_mfn_p; >>@@ -351,16 +351,16 @@ void __init >>xen_build_dynamic_phys_to_machine(void) >> >> xen_max_p2m_pfn = max_pfn; >> >>- p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> p2m_init(p2m_missing); >> >>- p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> p2m_mid_init(p2m_mid_missing); >> >>- p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> p2m_top_init(p2m_top); >> >>- p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> p2m_init(p2m_identity); >> >> /* >>@@ -373,7 +373,8 @@ void __init >xen_build_dynamic_phys_to_machine(void) >> unsigned mididx = p2m_mid_index(pfn); >> >> if (p2m_top[topidx] == p2m_mid_missing) { >>- unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE, >>+ false); >> p2m_mid_init(mid); >> >> p2m_top[topidx] = mid; >>@@ -609,7 +610,7 @@ static bool __init early_alloc_p2m_middle(unsigned >>long pfn, bool check_boundary >> return false; >> >> /* Boundary cross-over for the edges: */ >>- p2m = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ p2m = extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> >> p2m_init(p2m); >> >>@@ -635,7 +636,7 @@ static bool __init early_alloc_p2m(unsigned long >>pfn) >> mid = p2m_top[topidx]; >> mid_mfn_p = p2m_top_mfn_p[topidx]; >> if (mid == p2m_mid_missing) { >>- mid = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ mid = extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> >> p2m_mid_init(mid); >> >>@@ -645,7 +646,7 @@ static bool __init early_alloc_p2m(unsigned long >>pfn) >> } >> /* And the save/restore P2M tables.. */ >> if (mid_mfn_p == p2m_mid_missing_mfn) { >>- mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); >>+ mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE, false); >> p2m_mid_mfn_init(mid_mfn_p); >> >> p2m_top_mfn_p[topidx] = mid_mfn_p; >>@@ -858,7 +859,7 @@ static void __init m2p_override_init(void) >> unsigned i; >> >> m2p_overrides = extend_brk(sizeof(*m2p_overrides) * >M2P_OVERRIDE_HASH, >>- sizeof(unsigned long)); >>+ sizeof(unsigned long), false); >> >> for (i = 0; i < M2P_OVERRIDE_HASH; i++) >> INIT_LIST_HEAD(&m2p_overrides[i]); >>diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c >>index 4c1baa7..dff7fcc 100644 >>--- a/drivers/acpi/osl.c >>+++ b/drivers/acpi/osl.c >>@@ -563,7 +563,7 @@ RESERVE_BRK(acpi_override_tables_alloc, >>ACPI_OVERRIDE_TABLES_SIZE); >> void __init early_alloc_acpi_override_tables_buf(void) >> { >> acpi_tables_addr = __pa(extend_brk(ACPI_OVERRIDE_TABLES_SIZE, >>- PAGE_SIZE)); >>+ PAGE_SIZE, false)); >> } >> >> void __init acpi_initrd_override(void *data, size_t size)
On Wed, Aug 21, 2013 at 02:35:36PM +0200, H. Peter Anvin wrote: > Global symbols are inaccessible in physical mode. Even if they are embedded in the assembler code and use GLOBAL(paging_enabled) ? > > This is incidentally yet another example of "PV/weird platform violence", since in their absence it would be trivial to work around this by using segmentation. I don't follow why it could not. Why can't there be a __pa_symbol(paging_enabled) that is used. Won't that in effect allow you to check the contents of that 'global constant' even when you don't have paging enabled? > >>As mentioned above, on 32bit before paging is enabled, we have to > >>access variables > >>with pa. So introduce a "bool is_phys" parameter to extend_brk(), and > >>convert va > >>to pa is it is true. > > > >Could you do it differently? Meaning have a global symbol > >(paging_enabled) which will be used by most of the functions you > >changed in this patch and the next ones? It would naturally be enabled > >when paging is on and __va addresses can be used. > > > >That could also be used in the printk case to do a BUG_ON before paging > >is enabled on 32bit. Or perhaps use a different code path to deal with > >using __pa address. > > > >? -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote: >On Wed, Aug 21, 2013 at 02:35:36PM +0200, H. Peter Anvin wrote: >> Global symbols are inaccessible in physical mode. > >Even if they are embedded in the assembler code and use >GLOBAL(paging_enabled) ? Yes, because the address is different in physical mode. Think about it. You could do a *function* like: paging_enabled: mov (%esp),%edx xor %eax,%eax cmpl $PAGE_OFFSET,%edx setae %al ret >> >> This is incidentally yet another example of "PV/weird platform >violence", since in their absence it would be trivial to work around >this by using segmentation. > >I don't follow why it could not. > >Why can't there be a __pa_symbol(paging_enabled) that is used. Won't >that in effect allow you to check the contents of that 'global >constant' even when you don't have paging enabled? Yes. But not once paging has been turned on. >> >>As mentioned above, on 32bit before paging is enabled, we have to >> >>access variables >> >>with pa. So introduce a "bool is_phys" parameter to extend_brk(), >and >> >>convert va >> >>to pa is it is true. >> > >> >Could you do it differently? Meaning have a global symbol >> >(paging_enabled) which will be used by most of the functions you >> >changed in this patch and the next ones? It would naturally be >enabled >> >when paging is on and __va addresses can be used. >> > >> >That could also be used in the printk case to do a BUG_ON before >paging >> >is enabled on 32bit. Or perhaps use a different code path to deal >with >> >using __pa address. >> > >> >?
diff --git a/arch/x86/include/asm/dmi.h b/arch/x86/include/asm/dmi.h index fd8f9e2..3b51d81 100644 --- a/arch/x86/include/asm/dmi.h +++ b/arch/x86/include/asm/dmi.h @@ -9,7 +9,7 @@ static __always_inline __init void *dmi_alloc(unsigned len) { - return extend_brk(len, sizeof(int)); + return extend_brk(len, sizeof(int), false); } /* Use early IO mappings for DMI because it's initialized early */ diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h index 4f71d48..96d00da 100644 --- a/arch/x86/include/asm/setup.h +++ b/arch/x86/include/asm/setup.h @@ -75,7 +75,7 @@ extern struct boot_params boot_params; /* exceedingly early brk-like allocator */ extern unsigned long _brk_end; -void *extend_brk(size_t size, size_t align); +void *extend_brk(size_t size, size_t align, bool is_phys); /* * Reserve space in the brk section. The name must be unique within diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 51fcd5d..a189909 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -259,19 +259,27 @@ static inline void __init copy_edd(void) } #endif -void * __init extend_brk(size_t size, size_t align) +void * __init extend_brk(size_t size, size_t align, bool is_phys) { size_t mask = align - 1; void *ret; + unsigned long *brk_start, *brk_end, *brk_limit; - BUG_ON(_brk_start == 0); + brk_start = is_phys ? (unsigned long *)__pa_nodebug(&_brk_start) : + (unsigned long *)&_brk_start; + brk_end = is_phys ? (unsigned long *)__pa_nodebug(&_brk_end) : + (unsigned long *)&_brk_end; + brk_limit = is_phys ? (unsigned long *)__pa_nodebug(__brk_limit) : + (unsigned long *)__brk_limit; + + BUG_ON(*brk_start == 0); BUG_ON(align & mask); - _brk_end = (_brk_end + mask) & ~mask; - BUG_ON((char *)(_brk_end + size) > __brk_limit); + *brk_end = (*brk_end + mask) & ~mask; + BUG_ON((char *)(*brk_end + size) > brk_limit); - ret = (void *)_brk_end; - _brk_end += size; + ret = (void *)(*brk_end); + *brk_end += size; memset(ret, 0, size); diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 2ec29ac..189a9e2 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -86,7 +86,7 @@ void __init early_alloc_pgt_buf(void) unsigned long tables = INIT_PGT_BUF_SIZE; phys_addr_t base; - base = __pa(extend_brk(tables, PAGE_SIZE)); + base = __pa(extend_brk(tables, PAGE_SIZE, false)); pgt_buf_start = base >> PAGE_SHIFT; pgt_buf_end = pgt_buf_start; diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 193097e..2d5a34f 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1629,7 +1629,7 @@ void __ref xen_hvm_init_shared_info(void) if (!shared_info_page) shared_info_page = (struct shared_info *) - extend_brk(PAGE_SIZE, PAGE_SIZE); + extend_brk(PAGE_SIZE, PAGE_SIZE, false); xatp.domid = DOMID_SELF; xatp.idx = 0; xatp.space = XENMAPSPACE_shared_info; diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index fdc3ba2..573bc50 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -1768,7 +1768,7 @@ static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn) unsigned long pfn; level1_ident_pgt = extend_brk(sizeof(pte_t) * LEVEL1_IDENT_ENTRIES, - PAGE_SIZE); + PAGE_SIZE, false); ident_pte = 0; pfn = 0; @@ -1980,7 +1980,7 @@ static void __init xen_write_cr3_init(unsigned long cr3) * swapper_pg_dir. */ swapper_kernel_pmd = - extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE); + extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE, false); copy_page(swapper_kernel_pmd, initial_kernel_pmd); swapper_pg_dir[KERNEL_PGD_BOUNDARY] = __pgd(__pa(swapper_kernel_pmd) | _PAGE_PRESENT); @@ -2003,7 +2003,7 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn) pmd_t *kernel_pmd; initial_kernel_pmd = - extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE); + extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE, false); max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) + xen_start_info->nr_pt_frames * PAGE_SIZE + diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index 95fb2aa..bbdcf20 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -281,13 +281,13 @@ void __ref xen_build_mfn_list_list(void) /* Pre-initialize p2m_top_mfn to be completely missing */ if (p2m_top_mfn == NULL) { - p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); + p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE, false); p2m_mid_mfn_init(p2m_mid_missing_mfn); - p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); + p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE, false); p2m_top_mfn_p_init(p2m_top_mfn_p); - p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); + p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE, false); p2m_top_mfn_init(p2m_top_mfn); } else { /* Reinitialise, mfn's all change after migration */ @@ -322,7 +322,7 @@ void __ref xen_build_mfn_list_list(void) * runtime. extend_brk() will BUG if we call * it too late. */ - mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); + mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE, false); p2m_mid_mfn_init(mid_mfn_p); p2m_top_mfn_p[topidx] = mid_mfn_p; @@ -351,16 +351,16 @@ void __init xen_build_dynamic_phys_to_machine(void) xen_max_p2m_pfn = max_pfn; - p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); + p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE, false); p2m_init(p2m_missing); - p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); + p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE, false); p2m_mid_init(p2m_mid_missing); - p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE); + p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE, false); p2m_top_init(p2m_top); - p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE); + p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE, false); p2m_init(p2m_identity); /* @@ -373,7 +373,8 @@ void __init xen_build_dynamic_phys_to_machine(void) unsigned mididx = p2m_mid_index(pfn); if (p2m_top[topidx] == p2m_mid_missing) { - unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE); + unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE, + false); p2m_mid_init(mid); p2m_top[topidx] = mid; @@ -609,7 +610,7 @@ static bool __init early_alloc_p2m_middle(unsigned long pfn, bool check_boundary return false; /* Boundary cross-over for the edges: */ - p2m = extend_brk(PAGE_SIZE, PAGE_SIZE); + p2m = extend_brk(PAGE_SIZE, PAGE_SIZE, false); p2m_init(p2m); @@ -635,7 +636,7 @@ static bool __init early_alloc_p2m(unsigned long pfn) mid = p2m_top[topidx]; mid_mfn_p = p2m_top_mfn_p[topidx]; if (mid == p2m_mid_missing) { - mid = extend_brk(PAGE_SIZE, PAGE_SIZE); + mid = extend_brk(PAGE_SIZE, PAGE_SIZE, false); p2m_mid_init(mid); @@ -645,7 +646,7 @@ static bool __init early_alloc_p2m(unsigned long pfn) } /* And the save/restore P2M tables.. */ if (mid_mfn_p == p2m_mid_missing_mfn) { - mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); + mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE, false); p2m_mid_mfn_init(mid_mfn_p); p2m_top_mfn_p[topidx] = mid_mfn_p; @@ -858,7 +859,7 @@ static void __init m2p_override_init(void) unsigned i; m2p_overrides = extend_brk(sizeof(*m2p_overrides) * M2P_OVERRIDE_HASH, - sizeof(unsigned long)); + sizeof(unsigned long), false); for (i = 0; i < M2P_OVERRIDE_HASH; i++) INIT_LIST_HEAD(&m2p_overrides[i]); diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index 4c1baa7..dff7fcc 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -563,7 +563,7 @@ RESERVE_BRK(acpi_override_tables_alloc, ACPI_OVERRIDE_TABLES_SIZE); void __init early_alloc_acpi_override_tables_buf(void) { acpi_tables_addr = __pa(extend_brk(ACPI_OVERRIDE_TABLES_SIZE, - PAGE_SIZE)); + PAGE_SIZE, false)); } void __init acpi_initrd_override(void *data, size_t size)
We are going to do acpi_initrd_override() at very early time: On 32bit: do it in head_32.S, before paging is enabled. In this case, we can access initrd with physical address without page tables. On 64bit: do it in head_64.c, after paging is enabled but before direct mapping is setup. On 64bit, we have an early page fault handler to help to access data with direct mapping page tables. So it is easy to do in head_64.c. And we need to allocate memory to store override tables. At such an early time, no memory allocator works. So we can only use BRK. As mentioned above, on 32bit before paging is enabled, we have to access variables with pa. So introduce a "bool is_phys" parameter to extend_brk(), and convert va to pa is it is true. Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com> --- arch/x86/include/asm/dmi.h | 2 +- arch/x86/include/asm/setup.h | 2 +- arch/x86/kernel/setup.c | 20 ++++++++++++++------ arch/x86/mm/init.c | 2 +- arch/x86/xen/enlighten.c | 2 +- arch/x86/xen/mmu.c | 6 +++--- arch/x86/xen/p2m.c | 27 ++++++++++++++------------- drivers/acpi/osl.c | 2 +- 8 files changed, 36 insertions(+), 27 deletions(-)