From 247055aa21ffef1c49dd64710d5e94c2aee19b58 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Mon, 13 Sep 2010 16:03:21 +0100 Subject: ARM: 6384/1: Remove the domain switching on ARMv6k/v7 CPUs This patch removes the domain switching functionality via the set_fs and __switch_to functions on cores that have a TLS register. Currently, the ioremap and vmalloc areas share the same level 1 page tables and therefore have the same domain (DOMAIN_KERNEL). When the kernel domain is modified from Client to Manager (via the __set_fs or in the __switch_to function), the XN (eXecute Never) bit is overridden and newer CPUs can speculatively prefetch the ioremap'ed memory. Linux performs the kernel domain switching to allow user-specific functions (copy_to/from_user, get/put_user etc.) to access kernel memory. In order for these functions to work with the kernel domain set to Client, the patch modifies the LDRT/STRT and related instructions to the LDR/STR ones. The user pages access rights are also modified for kernel read-only access rather than read/write so that the copy-on-write mechanism still works. CPU_USE_DOMAINS gets disabled only if the hardware has a TLS register (CPU_32v6K is defined) since writing the TLS value to the high vectors page isn't possible. The user addresses passed to the kernel are checked by the access_ok() function so that they do not point to the kernel space. Tested-by: Anton Vorontsov Cc: Tony Lindgren Signed-off-by: Catalin Marinas Signed-off-by: Russell King --- arch/arm/include/asm/assembler.h | 13 +++++++------ arch/arm/include/asm/domain.h | 31 +++++++++++++++++++++++++++++-- arch/arm/include/asm/futex.h | 9 +++++---- arch/arm/include/asm/traps.h | 2 ++ arch/arm/include/asm/uaccess.h | 16 ++++++++-------- 5 files changed, 51 insertions(+), 20 deletions(-) (limited to 'arch/arm/include') diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 062b58c029ab..4e84d09c9c1b 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -18,6 +18,7 @@ #endif #include +#include /* * Endian independent macros for shifting bytes within registers. @@ -206,12 +207,12 @@ */ #ifdef CONFIG_THUMB2_KERNEL - .macro usraccoff, instr, reg, ptr, inc, off, cond, abort + .macro usraccoff, instr, reg, ptr, inc, off, cond, abort, t=T() 9999: .if \inc == 1 - \instr\cond\()bt \reg, [\ptr, #\off] + \instr\cond\()b\()\t\().w \reg, [\ptr, #\off] .elseif \inc == 4 - \instr\cond\()t \reg, [\ptr, #\off] + \instr\cond\()\t\().w \reg, [\ptr, #\off] .else .error "Unsupported inc macro argument" .endif @@ -246,13 +247,13 @@ #else /* !CONFIG_THUMB2_KERNEL */ - .macro usracc, instr, reg, ptr, inc, cond, rept, abort + .macro usracc, instr, reg, ptr, inc, cond, rept, abort, t=T() .rept \rept 9999: .if \inc == 1 - \instr\cond\()bt \reg, [\ptr], #\inc + \instr\cond\()b\()\t \reg, [\ptr], #\inc .elseif \inc == 4 - \instr\cond\()t \reg, [\ptr], #\inc + \instr\cond\()\t \reg, [\ptr], #\inc .else .error "Unsupported inc macro argument" .endif diff --git a/arch/arm/include/asm/domain.h b/arch/arm/include/asm/domain.h index cc7ef4080711..af18ceaacf5d 100644 --- a/arch/arm/include/asm/domain.h +++ b/arch/arm/include/asm/domain.h @@ -45,13 +45,17 @@ */ #define DOMAIN_NOACCESS 0 #define DOMAIN_CLIENT 1 +#ifdef CONFIG_CPU_USE_DOMAINS #define DOMAIN_MANAGER 3 +#else +#define DOMAIN_MANAGER 1 +#endif #define domain_val(dom,type) ((type) << (2*(dom))) #ifndef __ASSEMBLY__ -#ifdef CONFIG_MMU +#ifdef CONFIG_CPU_USE_DOMAINS #define set_domain(x) \ do { \ __asm__ __volatile__( \ @@ -74,5 +78,28 @@ #define modify_domain(dom,type) do { } while (0) #endif +/* + * Generate the T (user) versions of the LDR/STR and related + * instructions (inline assembly) + */ +#ifdef CONFIG_CPU_USE_DOMAINS +#define T(instr) #instr "t" +#else +#define T(instr) #instr #endif -#endif /* !__ASSEMBLY__ */ + +#else /* __ASSEMBLY__ */ + +/* + * Generate the T (user) versions of the LDR/STR and related + * instructions + */ +#ifdef CONFIG_CPU_USE_DOMAINS +#define T(instr) instr ## t +#else +#define T(instr) instr +#endif + +#endif /* __ASSEMBLY__ */ + +#endif /* !__ASM_PROC_DOMAIN_H */ diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h index 540a044153a5..b33fe7065b38 100644 --- a/arch/arm/include/asm/futex.h +++ b/arch/arm/include/asm/futex.h @@ -13,12 +13,13 @@ #include #include #include +#include #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \ __asm__ __volatile__( \ - "1: ldrt %1, [%2]\n" \ + "1: " T(ldr) " %1, [%2]\n" \ " " insn "\n" \ - "2: strt %0, [%2]\n" \ + "2: " T(str) " %0, [%2]\n" \ " mov %0, #0\n" \ "3:\n" \ " .pushsection __ex_table,\"a\"\n" \ @@ -97,10 +98,10 @@ futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval) pagefault_disable(); /* implies preempt_disable() */ __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" - "1: ldrt %0, [%3]\n" + "1: " T(ldr) " %0, [%3]\n" " teq %0, %1\n" " it eq @ explicit IT needed for the 2b label\n" - "2: streqt %2, [%3]\n" + "2: " T(streq) " %2, [%3]\n" "3:\n" " .pushsection __ex_table,\"a\"\n" " .align 3\n" diff --git a/arch/arm/include/asm/traps.h b/arch/arm/include/asm/traps.h index 491960bf4260..af5d5d1388c6 100644 --- a/arch/arm/include/asm/traps.h +++ b/arch/arm/include/asm/traps.h @@ -27,4 +27,6 @@ static inline int in_exception_text(unsigned long ptr) extern void __init early_trap_init(void); extern void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame); +extern void *vectors_page; + #endif diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 33e4a48fe103..b293616a1a1a 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -227,7 +227,7 @@ do { \ #define __get_user_asm_byte(x,addr,err) \ __asm__ __volatile__( \ - "1: ldrbt %1,[%2]\n" \ + "1: " T(ldrb) " %1,[%2],#0\n" \ "2:\n" \ " .pushsection .fixup,\"ax\"\n" \ " .align 2\n" \ @@ -263,7 +263,7 @@ do { \ #define __get_user_asm_word(x,addr,err) \ __asm__ __volatile__( \ - "1: ldrt %1,[%2]\n" \ + "1: " T(ldr) " %1,[%2],#0\n" \ "2:\n" \ " .pushsection .fixup,\"ax\"\n" \ " .align 2\n" \ @@ -308,7 +308,7 @@ do { \ #define __put_user_asm_byte(x,__pu_addr,err) \ __asm__ __volatile__( \ - "1: strbt %1,[%2]\n" \ + "1: " T(strb) " %1,[%2],#0\n" \ "2:\n" \ " .pushsection .fixup,\"ax\"\n" \ " .align 2\n" \ @@ -341,7 +341,7 @@ do { \ #define __put_user_asm_word(x,__pu_addr,err) \ __asm__ __volatile__( \ - "1: strt %1,[%2]\n" \ + "1: " T(str) " %1,[%2],#0\n" \ "2:\n" \ " .pushsection .fixup,\"ax\"\n" \ " .align 2\n" \ @@ -366,10 +366,10 @@ do { \ #define __put_user_asm_dword(x,__pu_addr,err) \ __asm__ __volatile__( \ - ARM( "1: strt " __reg_oper1 ", [%1], #4\n" ) \ - ARM( "2: strt " __reg_oper0 ", [%1]\n" ) \ - THUMB( "1: strt " __reg_oper1 ", [%1]\n" ) \ - THUMB( "2: strt " __reg_oper0 ", [%1, #4]\n" ) \ + ARM( "1: " T(str) " " __reg_oper1 ", [%1], #4\n" ) \ + ARM( "2: " T(str) " " __reg_oper0 ", [%1]\n" ) \ + THUMB( "1: " T(str) " " __reg_oper1 ", [%1]\n" ) \ + THUMB( "2: " T(str) " " __reg_oper0 ", [%1, #4]\n" ) \ "3:\n" \ " .pushsection .fixup,\"ax\"\n" \ " .align 2\n" \ -- cgit v1.2.1