diff options
author | Nicholas Piggin <npiggin@gmail.com> | 2016-09-28 11:31:48 +1000 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2016-10-04 13:06:56 +1100 |
commit | 57f266497d81e16141bd2c9009e91dad34ea5f70 (patch) | |
tree | cfe7f69e2945f26758dcb6a81c1a40b4ecfb73e9 /arch/powerpc/kernel/exceptions-64s.S | |
parent | 573819e3433278cde17e7b93e101e59e96f19ccf (diff) |
powerpc: Use gas sections for arranging exception vectors
Use assembler sections of fixed size and location to arrange the 64-bit
Book3S exception vector code (64-bit Book3E also uses it in head_64.S
for 0x0..0x100).
This allows better flexibility in arranging exception code and hiding
unimportant details behind macros.
Gas sections can be a bit painful to use this way, mainly because the
assembler does not know where they will be finally linked. Taking
absolute addresses requires a bit of trickery for example, but it can
be hidden behind macros for the most part.
Generated code is mostly the same except locations, offsets, alignments.
The "+ 0x2" is only required for the trap number / kvm exit number,
which gets loaded as a constant into a register.
Previously, code also used + 0x2 for label names, but we changed to
using "H" to distinguish HV case for that. Remove the last vestiges
of that.
__after_prom_start is taking absolute address of a label in another
fixed section. Newer toolchains seemed to compile this okay, but older
ones do not. FIXED_SYMBOL_ABS_ADDR is more foolproof, it just takes an
additional line to define.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/exceptions-64s.S')
-rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 111 |
1 files changed, 79 insertions, 32 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index d398e8716ef8..6ea330a3c51a 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -19,16 +19,68 @@ #include <asm/head-64.h> /* + * There are a few constraints to be concerned with. + * - Real mode exceptions code/data must be located at their physical location. + * - Virtual mode exceptions must be mapped at their 0xc000... location. + * - Fixed location code must not call directly beyond the __end_interrupts + * area when built with CONFIG_RELOCATABLE. LOAD_HANDLER / bctr sequence + * must be used. + * - LOAD_HANDLER targets must be within first 64K of physical 0 / + * virtual 0xc00... + * - Conditional branch targets must be within +/-32K of caller. + * + * "Virtual exceptions" run with relocation on (MSR_IR=1, MSR_DR=1), and + * therefore don't have to run in physically located code or rfid to + * virtual mode kernel code. However on relocatable kernels they do have + * to branch to KERNELBASE offset because the rest of the kernel (outside + * the exception vectors) may be located elsewhere. + * + * Virtual exceptions correspond with physical, except their entry points + * are offset by 0xc000000000000000 and also tend to get an added 0x4000 + * offset applied. Virtual exceptions are enabled with the Alternate + * Interrupt Location (AIL) bit set in the LPCR. However this does not + * guarantee they will be delivered virtually. Some conditions (see the ISA) + * cause exceptions to be delivered in real mode. + * + * It's impossible to receive interrupts below 0x300 via AIL. + * + * KVM: None of the virtual exceptions are from the guest. Anything that + * escalated to HV=1 from HV=0 is delivered via real mode handlers. + * + * * We layout physical memory as follows: * 0x0000 - 0x00ff : Secondary processor spin code - * 0x0100 - 0x17ff : pSeries Interrupt prologs - * 0x1800 - 0x4000 : interrupt support common interrupt prologs - * 0x4000 - 0x5fff : pSeries interrupts with IR=1,DR=1 - * 0x6000 - 0x6fff : more interrupt support including for IR=1,DR=1 + * 0x0100 - 0x18ff : Real mode pSeries interrupt vectors + * 0x1900 - 0x3fff : Real mode trampolines + * 0x4000 - 0x58ff : Relon (IR=1,DR=1) mode pSeries interrupt vectors + * 0x5900 - 0x6fff : Relon mode trampolines * 0x7000 - 0x7fff : FWNMI data area - * 0x8000 - 0x8fff : Initial (CPU0) segment table - * 0x9000 - : Early init and support code + * 0x8000 - .... : Common interrupt handlers, remaining early + * setup code, rest of kernel. + */ +OPEN_FIXED_SECTION(real_vectors, 0x0100, 0x1900) +OPEN_FIXED_SECTION(real_trampolines, 0x1900, 0x4000) +OPEN_FIXED_SECTION(virt_vectors, 0x4000, 0x5900) +OPEN_FIXED_SECTION(virt_trampolines, 0x5900, 0x7000) +#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV) +/* + * Data area reserved for FWNMI option. + * This address (0x7000) is fixed by the RPA. + * pseries and powernv need to keep the whole page from + * 0x7000 to 0x8000 free for use by the firmware */ +ZERO_FIXED_SECTION(fwnmi_page, 0x7000, 0x8000) +OPEN_TEXT_SECTION(0x8000) +#else +OPEN_TEXT_SECTION(0x7000) +#endif + +USE_FIXED_SECTION(real_vectors) + +#define LOAD_SYSCALL_HANDLER(reg) \ + ld reg,PACAKBASE(r13); \ + ori reg,reg,(ABS_ADDR(system_call_common))@l; + /* Syscall routine is used twice, in reloc-off and reloc-on paths */ #define SYSCALL_PSERIES_1 \ BEGIN_FTR_SECTION \ @@ -42,7 +94,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_REAL_LE) \ #define SYSCALL_PSERIES_2_RFID \ mfspr r12,SPRN_SRR1 ; \ - LOAD_HANDLER(r10, system_call_common) ; \ + LOAD_SYSCALL_HANDLER(r10) ; \ mtspr SPRN_SRR0,r10 ; \ ld r10,PACAKMSR(r13) ; \ mtspr SPRN_SRR1,r10 ; \ @@ -63,7 +115,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_REAL_LE) \ * is volatile across system calls. */ #define SYSCALL_PSERIES_2_DIRECT \ - LOAD_HANDLER(r12, system_call_common) ; \ + LOAD_SYSCALL_HANDLER(r12) ; \ mtctr r12 ; \ mfspr r12,SPRN_SRR1 ; \ li r10,MSR_RI ; \ @@ -86,7 +138,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_REAL_LE) \ * Therefore any relative branches in this section must only * branch to labels in this section. */ - . = 0x100 .globl __start_interrupts __start_interrupts: @@ -200,9 +251,6 @@ EXC_REAL_BEGIN(instruction_access_slb, 0x480, 0x500) #endif EXC_REAL_END(instruction_access_slb, 0x480, 0x500) - /* We open code these as we can't have a ". = x" (even with - * x = "." within a feature section - */ EXC_REAL_BEGIN(hardware_interrupt, 0x500, 0x600) .globl hardware_interrupt_hv; hardware_interrupt_hv: @@ -306,7 +354,6 @@ __EXC_REAL_OOL_HV(h_facility_unavailable, 0xf80, 0xfa0) EXC_REAL_NONE(0xfa0, 0x1200) - #ifdef CONFIG_CBE_RAS EXC_REAL_HV(cbe_system_error, 0x1200, 0x1300) @@ -359,7 +406,6 @@ TRAMP_KVM_HV_SKIP(PACA_EXGEN, 0x1800) #else /* CONFIG_CBE_RAS */ EXC_REAL_NONE(0x1800, 0x1900) - . = 0x1800 #endif @@ -606,7 +652,13 @@ masked_##_H##interrupt: \ GET_SCRATCH0(r13); \ ##_H##rfid; \ b . - + +/* + * Real mode exceptions actually use this too, but alternate + * instruction code patches (which end up in the common .text area) + * cannot reach these if they are put there. + */ +USE_FIXED_SECTION(virt_trampolines) MASKED_INTERRUPT() MASKED_INTERRUPT(H) @@ -620,6 +672,7 @@ masked_##_H##interrupt: \ * in the generated frame has EE set to 1 or the exception * handler will not properly re-enable them. */ +USE_TEXT_SECTION() _GLOBAL(__replay_interrupt) /* We are going to jump to the exception common code which * will retrieve various register values from the PACA which @@ -862,7 +915,7 @@ EXC_VIRT(altivec_assist, 0x5700, 0x5800, 0x1700) EXC_VIRT_NONE(0x5800, 0x5900) -TRAMP_REAL_BEGIN(ppc64_runlatch_on_trampoline) +EXC_COMMON_BEGIN(ppc64_runlatch_on_trampoline) b __ppc64_runlatch_on /* @@ -1070,6 +1123,7 @@ __TRAMP_REAL_VIRT_OOL(vsx_unavailable, 0xf40) __TRAMP_REAL_VIRT_OOL(facility_unavailable, 0xf60) __TRAMP_REAL_VIRT_OOL_HV(h_facility_unavailable, 0xf80) +USE_FIXED_SECTION(virt_trampolines) /* * The __end_interrupts marker must be past the out-of-line (OOL) * handlers, so that they are copied to real address 0x100 when running @@ -1080,21 +1134,7 @@ __TRAMP_REAL_VIRT_OOL_HV(h_facility_unavailable, 0xf80) .align 7 .globl __end_interrupts __end_interrupts: - -#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV) -/* - * Data area reserved for FWNMI option. - * This address (0x7000) is fixed by the RPA. - */ - .= 0x7000 - .globl fwnmi_data_area -fwnmi_data_area: - - /* pseries and powernv need to keep the whole page from - * 0x7000 to 0x8000 free for use by the firmware - */ - . = 0x8000 -#endif /* defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV) */ +DEFINE_FIXED_SYMBOL(__end_interrupts) EXC_COMMON(facility_unavailable_common, 0xf60, facility_unavailable_exception) EXC_COMMON(h_facility_unavailable_common, 0xf80, facility_unavailable_exception) @@ -1106,7 +1146,7 @@ EXC_COMMON(cbe_thermal_common, 0x1800, cbe_thermal_exception) #endif /* CONFIG_CBE_RAS */ -EXC_COMMON_BEGIN(hmi_exception_early) +TRAMP_REAL_BEGIN(hmi_exception_early) EXCEPTION_PROLOG_1(PACA_EXGEN, KVMTEST_HV, 0xe60) mr r10,r1 /* Save r1 */ ld r1,PACAEMERGSP(r13) /* Use emergency stack */ @@ -1430,6 +1470,13 @@ TRAMP_REAL_BEGIN(power4_fixup_nap) blr #endif +CLOSE_FIXED_SECTION(real_vectors); +CLOSE_FIXED_SECTION(real_trampolines); +CLOSE_FIXED_SECTION(virt_vectors); +CLOSE_FIXED_SECTION(virt_trampolines); + +USE_TEXT_SECTION() + /* * Hash table stuff */ |