- 18 May, 2020 40 commits
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Ravi Bangoria authored
With Book3s DAWR, ptrace and perf watchpoints on powerpc behaves differently. Ptrace watchpoint works in one-shot mode and generates signal before executing instruction. It's ptrace user's job to single-step the instruction and re-enable the watchpoint. OTOH, in case of perf watchpoint, kernel emulates/single-steps the instruction and then generates event. If perf and ptrace creates two events with same or overlapping address ranges, it's ambiguous to decide who should single-step the instruction. Because of this issue, don't allow perf and ptrace watchpoint at the same time if their address range overlaps. Signed-off-by:
Ravi Bangoria <ravi.bangoria@linux.ibm.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Reviewed-by:
Michael Neuling <mikey@neuling.org> Link: https://lore.kernel.org/r/20200514111741.97993-15-ravi.bangoria@linux.ibm.com
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Ravi Bangoria authored
Currently we assume that we have only one watchpoint supported by hw. Get rid of that assumption and use dynamic loop instead. This should make supporting more watchpoints very easy. With more than one watchpoint, exception handler needs to know which DAWR caused the exception, and hw currently does not provide it. So we need sw logic for the same. To figure out which DAWR caused the exception, check all different combinations of user specified range, DAWR address range, actual access range and DAWRX constrains. For ex, if user specified range and actual access range overlaps but DAWRX is configured for readonly watchpoint and the instruction is store, this DAWR must not have caused exception. Signed-off-by:
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Ravi Bangoria authored
Currently we calculate hw aligned start and end addresses manually. Replace them with builtin ALIGN_DOWN() and ALIGN() macros. So far end_addr was inclusive but this patch makes it exclusive (by avoiding -1) for better readability. Suggested-by:
Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by:
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Ravi Bangoria authored
Introduce is_ptrace_bp() function and move the check inside the function. It will be utilize more in later set of patches. Signed-off-by:
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Ravi Bangoria authored
ptrace_bps is already an array of size HBP_NUM_MAX. But we use hardcoded index 0 while fetching/updating it. Convert such code to loop over array. ptrace interface to use multiple watchpoint remains same. eg: two PPC_PTRACE_SETHWDEBUG calls will create two watchpoint if underneath hw supports it. Signed-off-by:
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Ravi Bangoria authored
So far powerpc hw supported only one watchpoint. But Power10 is introducing 2nd DAWR. Convert thread_struct->hw_brk into an array. Signed-off-by:
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Ravi Bangoria authored
Instead of disabling only first watchpoint, disable all available watchpoints while clearing dawr_force_enable. Callback function is used only for disabling watchpoint, rename it to disable_dawrs_cb(). And null_brk parameter is not really required while disabling watchpoint, remove it. Signed-off-by:
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Ravi Bangoria authored
Instead of disabling only one watchpoint, get num of available watchpoints dynamically and disable all of them. Signed-off-by:
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Ravi Bangoria authored
Introduce new parameter 'nr' to __set_breakpoint() which indicates which DAWR should be programed. Also convert current_brk variable to an array. Signed-off-by:
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Ravi Bangoria authored
Introduce new parameter 'nr' to set_dawr() which indicates which DAWR should be programed. Signed-off-by:
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Ravi Bangoria authored
User can ask for num of available watchpoints(dbginfo.num_data_bps) using ptrace(PPC_PTRACE_GETHWDBGINFO). Return actual number of available watchpoints on the machine rather than hardcoded 1. Signed-off-by:
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Ravi Bangoria authored
So far we had only one watchpoint, so we have hardcoded HBP_NUM to 1. But Power10 is introducing 2nd DAWR and thus kernel should be able to dynamically find actual number of watchpoints supported by hw it's running on. Introduce function for the same. Also convert HBP_NUM macro to HBP_NUM_MAX, which will now represent maximum number of watchpoints supported by Powerpc. Signed-off-by:
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Ravi Bangoria authored
Power10 is introducing second DAWR. Add SPRN_ macros for the same. Signed-off-by:
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Ravi Bangoria authored
Power10 is introducing second DAWR. Use real register names from ISA for current macros: s/SPRN_DAWR/SPRN_DAWR0/ s/SPRN_DAWRX/SPRN_DAWRX0/ Signed-off-by:
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Jordan Niethe authored
This adds emulation support for the following prefixed Fixed-Point Arithmetic instructions: * Prefixed Add Immediate (paddi) Signed-off-by:
Jordan Niethe <jniethe5@gmail.com> Reviewed-by:
Balamuruhan S <bala24@linux.ibm.com> [mpe: Squash in get_op() usage] Signed-off-by:
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Jordan Niethe authored
This adds emulation support for the following prefixed integer load/stores: * Prefixed Load Byte and Zero (plbz) * Prefixed Load Halfword and Zero (plhz) * Prefixed Load Halfword Algebraic (plha) * Prefixed Load Word and Zero (plwz) * Prefixed Load Word Algebraic (plwa) * Prefixed Load Doubleword (pld) * Prefixed Store Byte (pstb) * Prefixed Store Halfword (psth) * Prefixed Store Word (pstw) * Prefixed Store Doubleword (pstd) * Prefixed Load Quadword (plq) * Prefixed Store Quadword (pstq) the follow prefixed floating-point load/stores: * Prefixed Load Floating-Point Single (plfs) * Prefixed Load Floating-Point Double (plfd) * Prefixed Store Floating-Point Single (pstfs) * Prefixed Store Floating-Point Double (pstfd) and for the following prefixed VSX load/stores: * Prefixed Load VSX Scalar Doubleword (plxsd) * Prefixed Load VSX Scalar Single-Precision (plxssp) * Prefixed Load VSX Vector [0|1] (plxv, plxv0, plxv1) * Prefixed Store VSX Scalar Doubleword (pstxsd) * Prefixed Store VSX Scalar Single-Precision (pstxssp) * Prefixed Store VSX Vector [0|1] (pstxv, pstxv0, pstxv1) Signed-off-by:
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Jordan Niethe authored
If a prefixed instruction results in an alignment exception, the SRR1_PREFIXED bit is set. The handler attempts to emulate the responsible instruction and then increment the NIP past it. Use SRR1_PREFIXED to determine by how much the NIP should be incremented. Prefixed instructions are not permitted to cross 64-byte boundaries. If they do the alignment interrupt is invoked with SRR1 BOUNDARY bit set. If this occurs send a SIGBUS to the offending process if in user mode. If in kernel mode call bad_page_fault(). Signed-off-by:
Alistair Popple <alistair@popple.id.au> Link: https://lore.kernel.org/r/20200506034050.24806-29-jniethe5@gmail.com
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Jordan Niethe authored
Do not allow inserting breakpoints on the suffix of a prefix instruction in kprobes. Signed-off-by:
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Jordan Niethe authored
Do not allow placing xmon breakpoints on the suffix of a prefix instruction. Signed-off-by:
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Jordan Niethe authored
Expand the feature-fixups self-tests to includes tests for prefixed instructions. Signed-off-by:
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Jordan Niethe authored
Expand the code-patching self-tests to includes tests for patching prefixed instructions. Signed-off-by:
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Jordan Niethe authored
For powerpc64, redefine the ppc_inst type so both word and prefixed instructions can be represented. On powerpc32 the type will remain the same. Update places which had assumed instructions to be 4 bytes long. Signed-off-by:
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Jordan Niethe authored
Currently patch_imm32_load_insns() is used to load an instruction to r4 to be emulated by emulate_step(). For prefixed instructions we would like to be able to load a 64bit immediate to r4. To prepare for this make patch_imm64_load_insns() take an argument that decides which register to load an immediate to - rather than hardcoding r3. Signed-off-by:
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Jordan Niethe authored
Add the BOUNDARY SRR1 bit definition for when the cause of an alignment exception is a prefixed instruction that crosses a 64-byte boundary. Add the PREFIXED SRR1 bit definition for exceptions caused by prefixed instructions. Bit 35 of SRR1 is called SRR1_ISI_N_OR_G. This name comes from it being used to indicate that an ISI was due to the access being no-exec or guarded. ISA v3.1 adds another purpose. It is also set if there is an access in a cache-inhibited location for prefixed instruction. Rename from SRR1_ISI_N_OR_G to SRR1_ISI_N_G_OR_CIP. Signed-off-by:
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Alistair Popple authored
Prefix instructions have their own FSCR bit which needs to enabled via a CPU feature. The kernel will save the FSCR for problem state but it needs to be enabled initially. If prefixed instructions are made unavailable by the [H]FSCR, attempting to use them will cause a facility unavailable exception. Add "PREFIX" to the facility_strings[]. Currently there are no prefixed instructions that are actually emulated by emulate_instruction() within facility_unavailable_exception(). However, when caused by a prefixed instructions the SRR1 PREFIXED bit is set. Prepare for dealing with emulated prefixed instructions by checking for this bit. Signed-off-by:
Nicholas Piggin <npiggin@gmail.com> Link: https://lore.kernel.org/r/20200506034050.24806-22-jniethe5@gmail.com
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Jordan Niethe authored
test_translate_branch() uses two pointers to instructions within a buffer, p and q, to test patch_branch(). The pointer arithmetic done on them assumes a size of 4. This will not work if the instruction length changes. Instead do the arithmetic relative to the void * to the buffer. Signed-off-by:
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Jordan Niethe authored
When a new breakpoint is created, the second instruction of that breakpoint is patched with a trap instruction. This assumes the length of the instruction is always the same. In preparation for prefixed instructions, remove this assumption. Insert the trap instruction at the same time the first instruction is inserted. Signed-off-by:
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Jordan Niethe authored
Currently in xmon, mread() is used for reading instructions. In preparation for prefixed instructions, create and use a new function, mread_instr(), especially for reading instructions. Signed-off-by:
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Jordan Niethe authored
Currently all instructions have the same length, but in preparation for prefixed instructions introduce a function for returning instruction length. Signed-off-by:
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Jordan Niethe authored
Define specialised get_user_instr(), __get_user_instr() and __get_user_instr_inatomic() macros for reading instructions from user and/or kernel space. Signed-off-by:
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Jordan Niethe authored
Instead of using memcpy() and flush_icache_range() use patch_instruction() which not only accomplishes both of these steps but will also make it easier to add support for prefixed instructions. Signed-off-by:
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Jordan Niethe authored
Introduce a probe_kernel_read_inst() function to use in cases where probe_kernel_read() is used for getting an instruction. This will be more useful for prefixed instructions. Signed-off-by:
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Jordan Niethe authored
Introduce a probe_user_read_inst() function to use in cases where probe_user_read() is used for getting an instruction. This will be more useful for prefixed instructions. Signed-off-by:
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Jordan Niethe authored
Prefixed instructions will mean there are instructions of different length. As a result dereferencing a pointer to an instruction will not necessarily give the desired result. Introduce a function for reading instructions from memory into the instruction data type. Signed-off-by:
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Jordan Niethe authored
Currently unsigned ints are used to represent instructions on powerpc. This has worked well as instructions have always been 4 byte words. However, ISA v3.1 introduces some changes to instructions that mean this scheme will no longer work as well. This change is Prefixed Instructions. A prefixed instruction is made up of a word prefix followed by a word suffix to make an 8 byte double word instruction. No matter the endianness of the system the prefix always comes first. Prefixed instructions are only planned for powerpc64. Introduce a ppc_inst type to represent both prefixed and word instructions on powerpc64 while keeping it possible to exclusively have word instructions on powerpc32. Signed-off-by:
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Jordan Niethe authored
In preparation for an instruction data type that can not be directly used with the '==' operator use functions for checking equality. Signed-off-by:
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Jordan Niethe authored
Use a function for byte swapping instructions in preparation of a more complicated instruction type. Signed-off-by:
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Jordan Niethe authored
In preparation for using a data type for instructions that can not be directly used with the '>>' operator use a function for getting the op code of an instruction. Signed-off-by:
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Jordan Niethe authored
In preparation for introducing a more complicated instruction type to accommodate prefixed instructions use an accessor for getting an instruction as a u32. Signed-off-by:
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Jordan Niethe authored
In preparation for instructions having a more complex data type start using a macro, ppc_inst(), for making an instruction out of a u32. A macro is used so that instructions can be used as initializer elements. Currently this does nothing, but it will allow for creating a data type that can represent prefixed instructions. Signed-off-by:
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