[for-next][PATCH 46/46] tracing: Rewrite filter logic to be simpler and faster

Steven Rostedt
2018-03-21T02:22:11Z

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From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Al Viro reviewed the filter logic of ftrace trace events and found it to be
very troubling. It creates a binary tree based on the logic operators and
walks it during tracing. He sent myself and Tom Zanussi a long explanation
(and formal proof) of how to do the string parsing better and end up with a
program array that can be simply iterated to come up with the correct
results.

I took his ideas and his pseudo code and rewrote the filter logic based on
them. In doing so, I was able to remove a lot of code, and have a much more
condensed filter logic in the process. I wrote a very long comment
describing the methadology that Al proposed in my own words. For more info
on how this works, read the comment above predicate_parse().

Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace.h | 15 +-
kernel/trace/trace_events_filter.c | 2311 ++++++++++++++++--------------------
2 files changed, 1054 insertions(+), 1272 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 9de3e2a2f042..6fb46a06c9dc 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1216,12 +1216,11 @@ struct ftrace_event_field {
int is_signed;
};

+struct prog_entry;
+
struct event_filter {
- int n_preds; /* Number assigned */
- int a_preds; /* allocated */
- struct filter_pred __rcu *preds;
- struct filter_pred __rcu *root;
- char *filter_string;
+ struct prog_entry __rcu *prog;
+ char *filter_string;
};

struct event_subsystem {
@@ -1413,12 +1412,8 @@ struct filter_pred {
unsigned short *ops;
struct ftrace_event_field *field;
int offset;
- int not;
+ int not;
int op;
- unsigned short index;
- unsigned short parent;
- unsigned short left;
- unsigned short right;
};

static inline bool is_string_field(struct ftrace_event_field *field)
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 9d383f4383dc..703a416aa5c2 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -33,60 +33,52 @@
"# Only events with the given fields will be affected.\n" \
"# If no events are modified, an error message will be displayed here"

+/* Due to token parsing '<=' must be before '<' and '>=' must be before '>' */
#define OPS \
- C( OP_OR, "||", 1 ), \
- C( OP_AND, "&&", 2 ), \
- C( OP_GLOB, "~", 4 ), \
- C( OP_NE, "!=", 4 ), \
- C( OP_EQ, "==", 4 ), \
- C( OP_LT, "<", 5 ), \
- C( OP_LE, "<=", 5 ), \
- C( OP_GT, ">", 5 ), \
- C( OP_GE, ">=", 5 ), \
- C( OP_BAND, "&", 6 ), \
- C( OP_NOT, "!", 6 ), \
- C( OP_NONE, "OP_NONE", 0 ), \
- C( OP_OPEN_PAREN, "(", 0 ), \
- C( OP_MAX, NULL, 0 )
+ C( OP_GLOB, "~" ), \
+ C( OP_NE, "!=" ), \
+ C( OP_EQ, "==" ), \
+ C( OP_LE, "<=" ), \
+ C( OP_LT, "<" ), \
+ C( OP_GE, ">=" ), \
+ C( OP_GT, ">" ), \
+ C( OP_BAND, "&" ), \
+ C( OP_MAX, NULL )

#undef C
-#define C(a, b, c) a
+#define C(a, b) a

enum filter_op_ids { OPS };

-struct filter_op {
- int id;
- char *string;
- int precedence;
-};
-
#undef C
-#define C(a, b, c) { a, b, c }
+#define C(a, b) b

-static struct filter_op filter_ops[] = { OPS };
+static const char * ops[] = { OPS };

/*
- * pred functions are OP_LT, OP_LE, OP_GT, OP_GE, and OP_BAND
+ * pred functions are OP_LE, OP_LT, OP_GE, OP_GT, and OP_BAND
* pred_funcs_##type below must match the order of them above.
*/
-#define PRED_FUNC_START OP_LT
+#define PRED_FUNC_START OP_LE
#define PRED_FUNC_MAX (OP_BAND - PRED_FUNC_START)

#define ERRORS \
- C( NONE, "No error"), \
- C( INVALID_OP, "Invalid operator"), \
- C( UNBALANCED_PAREN, "Unbalanced parens"), \
- C( TOO_MANY_OPERANDS, "Too many operands"), \
- C( OPERAND_TOO_LONG, "Operand too long"), \
- C( FIELD_NOT_FOUND, "Field not found"), \
- C( ILLEGAL_FIELD_OP, "Illegal operation for field type"), \
- C( ILLEGAL_INTVAL, "Illegal integer value"), \
- C( BAD_SUBSYS_FILTER, "Couldn't find or set field in one of a subsystem's events"), \
- C( TOO_MANY_PREDS, "Too many terms in predicate expression"), \
- C( MISSING_FIELD, "Missing field name and/or value"), \
- C( INVALID_FILTER, "Meaningless filter expression"), \
- C( IP_FIELD_ONLY, "Only 'ip' field is supported for function trace"), \
- C( ILLEGAL_NOT_OP, "Illegal use of '!'"),
+ C(NONE, "No error"), \
+ C(INVALID_OP, "Invalid operator"), \
+ C(TOO_MANY_OPEN, "Too many '('"), \
+ C(TOO_MANY_CLOSE, "Too few '('"), \
+ C(MISSING_QUOTE, "Missing matching quote"), \
+ C(OPERAND_TOO_LONG, "Operand too long"), \
+ C(EXPECT_STRING, "Expecting string field"), \
+ C(EXPECT_DIGIT, "Expecting numeric field"), \
+ C(ILLEGAL_FIELD_OP, "Illegal operation for field type"), \
+ C(FIELD_NOT_FOUND, "Field not found"), \
+ C(ILLEGAL_INTVAL, "Illegal integer value"), \
+ C(BAD_SUBSYS_FILTER, "Couldn't find or set field in one of a subsystem's events"), \
+ C(TOO_MANY_PREDS, "Too many terms in predicate expression"), \
+ C(INVALID_FILTER, "Meaningless filter expression"), \
+ C(IP_FIELD_ONLY, "Only 'ip' field is supported for function trace"), \
+ C(INVALID_VALUE, "Invalid value (did you forget quotes)?"),

#undef C
#define C(a, b) FILT_ERR_##a
@@ -98,84 +90,535 @@ enum { ERRORS };

static char *err_text[] = { ERRORS };

-struct opstack_op {
- enum filter_op_ids op;
- struct list_head list;
-};
+/* Called after a '!' character but "!=" and "!~" are not "not"s */
+static bool is_not(const char *str)
+{
+ switch (str[1]) {
+ case '=':
+ case '~':
+ return false;
+ }
+ return true;
+}

-struct postfix_elt {
- enum filter_op_ids op;
- char *operand;
- struct list_head list;
+/**
+ * prog_entry - a singe entry in the filter program
+ * @target: Index to jump to on a branch (actually one minus the index)
+ * @when_to_branch: The value of the result of the predicate to do a branch
+ * @pred: The predicate to execute.
+ */
+struct prog_entry {
+ int target;
+ int when_to_branch;
+ struct filter_pred *pred;
};

-struct filter_parse_state {
- struct filter_op *ops;
- struct list_head opstack;
- struct list_head postfix;
+/**
+ * update_preds- assign a program entry a label target
+ * @prog: The program array
+ * @N: The index of the current entry in @prog
+ * @when_to_branch: What to assign a program entry for its branch condition
+ *
+ * The program entry at @N has a target that points to the index of a program
+ * entry that can have its target and when_to_branch fields updated.
+ * Update the current program entry denoted by index @N target field to be
+ * that of the updated entry. This will denote the entry to update if
+ * we are processing an "||" after an "&&"
+ */
+static void update_preds(struct prog_entry *prog, int N, int invert)
+{
+ int t, s;
+
+ t = prog[N].target;
+ s = prog[t].target;
+ prog[t].when_to_branch = invert;
+ prog[t].target = N;
+ prog[N].target = s;
+}
+
+struct filter_parse_error {
int lasterr;
int lasterr_pos;
-
- struct {
- char *string;
- unsigned int cnt;
- unsigned int tail;
- } infix;
-
- struct {
- char string[MAX_FILTER_STR_VAL];
- int pos;
- unsigned int tail;
- } operand;
};

-struct pred_stack {
- struct filter_pred **preds;
- int index;
+static void parse_error(struct filter_parse_error *pe, int err, int pos)
+{
+ pe->lasterr = err;
+ pe->lasterr_pos = pos;
+}
+
+typedef int (*parse_pred_fn)(const char *str, void *data, int pos,
+ struct filter_parse_error *pe,
+ struct filter_pred **pred);
+
+enum {
+ INVERT = 1,
+ PROCESS_AND = 2,
+ PROCESS_OR = 4,
};

-/* If not of not match is equal to not of not, then it is a match */
+/*
+ * Without going into a formal proof, this explains the method that is used in
+ * parsing the logical expressions.
+ *
+ * For example, if we have: "a && !(!b || (c && g)) || d || e && !f"
+ * The first pass will convert it into the following program:
+ *
+ * n1: r=a; l1: if (!r) goto l4;
+ * n2: r=b; l2: if (!r) goto l4;
+ * n3: r=c; r=!r; l3: if (r) goto l4;
+ * n4: r=g; r=!r; l4: if (r) goto l5;
+ * n5: r=d; l5: if (r) goto T
+ * n6: r=e; l6: if (!r) goto l7;
+ * n7: r=f; r=!r; l7: if (!r) goto F
+ * T: return TRUE
+ * F: return FALSE
+ *
+ * To do this, we use a data structure to represent each of the above
+ * predicate and conditions that has:
+ *
+ * predicate, when_to_branch, invert, target
+ *
+ * The "predicate" will hold the function to determine the result "r".
+ * The "when_to_branch" denotes what "r" should be if a branch is to be taken
+ * "&&" would contain "!r" or (0) and "||" would contain "r" or (1).
+ * The "invert" holds whether the value should be reversed before testing.
+ * The "target" contains the label "l#" to jump to.
+ *
+ * A stack is created to hold values when parentheses are used.
+ *
+ * To simplify the logic, the labels will start at 0 and not 1.
+ *
+ * The possible invert values are 1 and 0. The number of "!"s that are in scope
+ * before the predicate determines the invert value, if the number is odd then
+ * the invert value is 1 and 0 otherwise. This means the invert value only
+ * needs to be toggled when a new "!" is introduced compared to what is stored
+ * on the stack, where parentheses were used.
+ *
+ * The top of the stack and "invert" are initialized to zero.
+ *
+ * ** FIRST PASS **
+ *
+ * #1 A loop through all the tokens is done:
+ *
+ * #2 If the token is an "(", the stack is push, and the current stack value
+ * gets the current invert value, and the loop continues to the next token.
+ * The top of the stack saves the "invert" value to keep track of what
+ * the current inversion is. As "!(a && !b || c)" would require all
+ * predicates being affected separately by the "!" before the parentheses.
+ * And that would end up being equivalent to "(!a || b) && !c"
+ *
+ * #3 If the token is an "!", the current "invert" value gets inverted, and
+ * the loop continues. Note, if the next token is a predicate, then
+ * this "invert" value is only valid for the current program entry,
+ * and does not affect other predicates later on.
+ *
+ * The only other acceptable token is the predicate string.
+ *
+ * #4 A new entry into the program is added saving: the predicate and the
+ * current value of "invert". The target is currently assigned to the
+ * previous program index (this will not be its final value).
+ *
+ * #5 We now enter another loop and look at the next token. The only valid
+ * tokens are ")", "&&", "||" or end of the input string "\0".
+ *
+ * #6 The invert variable is reset to the current value saved on the top of
+ * the stack.
+ *
+ * #7 The top of the stack holds not only the current invert value, but also
+ * if a "&&" or "||" needs to be processed. Note, the "&&" takes higher
+ * precedence than "||". That is "a && b || c && d" is equivalent to
+ * "(a && b) || (c && d)". Thus the first thing to do is to see if "&&" needs
+ * to be processed. This is the case if an "&&" was the last token. If it was
+ * then we call update_preds(). This takes the program, the current index in
+ * the program, and the current value of "invert". More will be described
+ * below about this function.
+ *
+ * #8 If the next token is "&&" then we set a flag in the top of the stack
+ * that denotes that "&&" needs to be processed, break out of this loop
+ * and continue with the outer loop.
+ *
+ * #9 Otherwise, if a "||" needs to be processed then update_preds() is called.
+ * This is called with the program, the current index in the program, but
+ * this time with an inverted value of "invert" (that is !invert). This is
+ * because the value taken will become the "when_to_branch" value of the
+ * program.
+ * Note, this is called when the next token is not an "&&". As stated before,
+ * "&&" takes higher precedence, and "||" should not be processed yet if the
+ * next logical operation is "&&".
+ *
+ * #10 If the next token is "||" then we set a flag in the top of the stack
+ * that denotes that "||" needs to be processed, break out of this loop
+ * and continue with the outer loop.
+ *
+ * #11 If this is the end of the input string "\0" then we break out of both
+ * loops.
+ *
+ * #12 Otherwise, the next token is ")", where we pop the stack and continue
+ * this inner loop.
+ *
+ * Now to discuss the update_pred() function, as that is key to the setting up
+ * of the program. Remember the "target" of the program is initialized to the
+ * previous index and not the "l" label. The target holds the index into the
+ * program that gets affected by the operand. Thus if we have something like
+ * "a || b && c", when we process "a" the target will be "-1" (undefined).
+ * When we process "b", its target is "0", which is the index of "a", as that's
+ * the predicate that is affected by "||". But because the next token after "b"
+ * is "&&" we don't call update_preds(). Instead continue to "c". As the
+ * next token after "c" is not "&&" but the end of input, we first process the
+ * "&&" by calling update_preds() for the "&&" then we process the "||" by
+ * callin updates_preds() with the values for processing "||".
+ *
+ * What does that mean? What update_preds() does is to first save the "target"
+ * of the program entry indexed by the current program entry's "target"
+ * (remember the "target" is initialized to previous program entry), and then
+ * sets that "target" to the current index which represents the label "l#".
+ * That entry's "when_to_branch" is set to the value passed in (the "invert"
+ * or "!invert"). Then it sets the current program entry's target to the saved
+ * "target" value (the old value of the program that had its "target" updated
+ * to the label).
+ *
+ * Looking back at "a || b && c", we have the following steps:
+ * "a" - prog[0] = { "a", X, -1 } // pred, when_to_branch, target
+ * "||" - flag that we need to process "||"; continue outer loop
+ * "b" - prog[1] = { "b", X, 0 }
+ * "&&" - flag that we need to process "&&"; continue outer loop
+ * (Notice we did not process "||")
+ * "c" - prog[2] = { "c", X, 1 }
+ * update_preds(prog, 2, 0); // invert = 0 as we are processing "&&"
+ * t = prog[2].target; // t = 1
+ * s = prog[t].target; // s = 0
+ * prog[t].target = 2; // Set target to "l2"
+ * prog[t].when_to_branch = 0;
+ * prog[2].target = s;
+ * update_preds(prog, 2, 1); // invert = 1 as we are now processing "||"
+ * t = prog[2].target; // t = 0
+ * s = prog[t].target; // s = -1
+ * prog[t].target = 2; // Set target to "l2"
+ * prog[t].when_to_branch = 1;
+ * prog[2].target = s;
+ *
+ * #13 Which brings us to the final step of the first pass, which is to set
+ * the last program entry's when_to_branch and target, which will be
+ * when_to_branch = 0; target = N; ( the label after the program entry after
+ * the last program entry processed above).
+ *
+ * If we denote "TRUE" to be the entry after the last program entry processed,
+ * and "FALSE" the program entry after that, we are now done with the first
+ * pass.
+ *
+ * Making the above "a || b && c" have a progam of:
+ * prog[0] = { "a", 1, 2 }
+ * prog[1] = { "b", 0, 2 }
+ * prog[2] = { "c", 0, 3 }
+ *
+ * Which translates into:
+ * n0: r = a; l0: if (r) goto l2;
+ * n1: r = b; l1: if (!r) goto l2;
+ * n2: r = c; l2: if (!r) goto l3; // Which is the same as "goto F;"
+ * T: return TRUE; l3:
+ * F: return FALSE
+ *
+ * Although, after the first pass, the program is correct, it is
+ * inefficient. The simple sample of "a || b && c" could be easily been
+ * converted into:
+ * n0: r = a; if (r) goto T
+ * n1: r = b; if (!r) goto F
+ * n2: r = c; if (!r) goto F
+ * T: return TRUE;
+ * F: return FALSE;
+ *
+ * The First Pass is over the input string. The next too passes are over
+ * the program itself.
+ *
+ * ** SECOND PASS **
+ *
+ * Which brings us to the second pass. If a jump to a label has the
+ * same condition as that label, it can instead jump to its target.
+ * The original example of "a && !(!b || (c && g)) || d || e && !f"
+ * where the first pass gives us:
+ *
+ * n1: r=a; l1: if (!r) goto l4;
+ * n2: r=b; l2: if (!r) goto l4;
+ * n3: r=c; r=!r; l3: if (r) goto l4;
+ * n4: r=g; r=!r; l4: if (r) goto l5;
+ * n5: r=d; l5: if (r) goto T
+ * n6: r=e; l6: if (!r) goto l7;
+ * n7: r=f; r=!r; l7: if (!r) goto F:
+ * T: return TRUE;
+ * F: return FALSE
+ *
+ * We can see that "l3: if (r) goto l4;" and at l4, we have "if (r) goto l5;".
+ * And "l5: if (r) goto T", we could optimize this by converting l3 and l4
+ * to go directly to T. To accomplish this, we start from the last
+ * entry in the program and work our way back. If the target of the entry
+ * has the same "when_to_branch" then we could use that entry's target.
+ * Doing this, the above would end up as:
+ *
+ * n1: r=a; l1: if (!r) goto l4;
+ * n2: r=b; l2: if (!r) goto l4;
+ * n3: r=c; r=!r; l3: if (r) goto T;
+ * n4: r=g; r=!r; l4: if (r) goto T;
+ * n5: r=d; l5: if (r) goto T;
+ * n6: r=e; l6: if (!r) goto F;
+ * n7: r=f; r=!r; l7: if (!r) goto F;
+ * T: return TRUE
+ * F: return FALSE
+ *
+ * In that same pass, if the "when_to_branch" doesn't match, we can simply
+ * go to the program entry after the label. That is, "l2: if (!r) goto l4;"
+ * where "l4: if (r) goto T;", then we can convert l2 to be:
+ * "l2: if (!r) goto n5;".
+ *
+ * This will have the second pass give us:
+ * n1: r=a; l1: if (!r) goto n5;
+ * n2: r=b; l2: if (!r) goto n5;
+ * n3: r=c; r=!r; l3: if (r) goto T;
+ * n4: r=g; r=!r; l4: if (r) goto T;
+ * n5: r=d; l5: if (r) goto T
+ * n6: r=e; l6: if (!r) goto F;
+ * n7: r=f; r=!r; l7: if (!r) goto F
+ * T: return TRUE
+ * F: return FALSE
+ *
+ * Notice, all the "l#" labels are no longer used, and they can now
+ * be discarded.
+ *
+ * ** THIRD PASS **
+ *
+ * For the third pass we deal with the inverts. As they simply just
+ * make the "when_to_branch" get inverted, a simple loop over the
+ * program to that does: "when_to_branch ^= invert;" will do the
+ * job, leaving us with:
+ * n1: r=a; if (!r) goto n5;
+ * n2: r=b; if (!r) goto n5;
+ * n3: r=c: if (!r) goto T;
+ * n4: r=g; if (!r) goto T;
+ * n5: r=d; if (r) goto T
+ * n6: r=e; if (!r) goto F;
+ * n7: r=f; if (r) goto F
+ * T: return TRUE
+ * F: return FALSE
+ *
+ * As "r = a; if (!r) goto n5;" is obviously the same as
+ * "if (!a) goto n5;" without doing anything we can interperate the
+ * program as:
+ * n1: if (!a) goto n5;
+ * n2: if (!b) goto n5;
+ * n3: if (!c) goto T;
+ * n4: if (!g) goto T;
+ * n5: if (d) goto T
+ * n6: if (!e) goto F;
+ * n7: if (f) goto F
+ * T: return TRUE
+ * F: return FALSE
+ *
+ * Since the inverts are discarded at the end, there's no reason to store
+ * them in the program array (and waste memory). A separate array to hold
+ * the inverts is used and freed at the end.
+ */
+static struct prog_entry *
+predicate_parse(const char *str, int nr_parens, int nr_preds,
+ parse_pred_fn parse_pred, void *data,
+ struct filter_parse_error *pe)
+{
+ struct prog_entry *prog_stack;
+ struct prog_entry *prog;
+ const char *ptr = str;
+ char *inverts = NULL;
+ int *op_stack;
+ int *top;
+ int invert = 0;
+ int ret = -ENOMEM;
+ int len;
+ int N = 0;
+ int i;
+
+ nr_preds += 2; /* For TRUE and FALSE */
+
+ op_stack = kmalloc(sizeof(*op_stack) * nr_parens, GFP_KERNEL);
+ if (!op_stack)
+ return ERR_PTR(-ENOMEM);
+ prog_stack = kmalloc(sizeof(*prog_stack) * nr_preds, GFP_KERNEL);
+ if (!prog_stack) {
+ parse_error(pe, -ENOMEM, 0);
+ goto out_free;
+ }
+ inverts = kmalloc(sizeof(*inverts) * nr_preds, GFP_KERNEL);
+ if (!inverts) {
+ parse_error(pe, -ENOMEM, 0);
+ goto out_free;
+ }
+
+ top = op_stack;
+ prog = prog_stack;
+ *top = 0;
+
+ /* First pass */
+ while (*ptr) { /* #1 */
+ const char *next = ptr++;
+
+ if (isspace(*next))
+ continue;
+
+ switch (*next) {
+ case '(': /* #2 */
+ if (top - op_stack > nr_parens)
+ return ERR_PTR(-EINVAL);
+ *(++top) = invert;
+ continue;
+ case '!': /* #3 */
+ if (!is_not(next))
+ break;
+ invert = !invert;
+ continue;
+ }
+
+ if (N >= nr_preds) {
+ parse_error(pe, FILT_ERR_TOO_MANY_PREDS, next - str);
+ goto out_free;
+ }
+
+ inverts[N] = invert; /* #4 */
+ prog[N].target = N-1;
+
+ len = parse_pred(next, data, ptr - str, pe, &prog[N].pred);
+ if (len < 0) {
+ ret = len;
+ goto out_free;
+ }
+ ptr = next + len;
+
+ N++;
+
+ ret = -1;
+ while (1) { /* #5 */
+ next = ptr++;
+ if (isspace(*next))
+ continue;
+
+ switch (*next) {
+ case ')':
+ case '\0':
+ break;
+ case '&':
+ case '|':
+ if (next[1] == next[0]) {
+ ptr++;
+ break;
+ }
+ default:
+ parse_error(pe, FILT_ERR_TOO_MANY_PREDS,
+ next - str);
+ goto out_free;
+ }
+
+ invert = *top & INVERT;
+
+ if (*top & PROCESS_AND) { /* #7 */
+ update_preds(prog, N - 1, invert);
+ *top &= ~PROCESS_AND;
+ }
+ if (*next == '&') { /* #8 */
+ *top |= PROCESS_AND;
+ break;
+ }
+ if (*top & PROCESS_OR) { /* #9 */
+ update_preds(prog, N - 1, !invert);
+ *top &= ~PROCESS_OR;
+ }
+ if (*next == '|') { /* #10 */
+ *top |= PROCESS_OR;
+ break;
+ }
+ if (!*next) /* #11 */
+ goto out;
+
+ if (top == op_stack) {
+ ret = -1;
+ /* Too few '(' */
+ parse_error(pe, FILT_ERR_TOO_MANY_CLOSE, ptr - str);
+ goto out_free;
+ }
+ top--; /* #12 */
+ }
+ }
+ out:
+ if (top != op_stack) {
+ /* Too many '(' */
+ parse_error(pe, FILT_ERR_TOO_MANY_OPEN, ptr - str);
+ goto out_free;
+ }
+
+ prog[N].pred = NULL; /* #13 */
+ prog[N].target = 1; /* TRUE */
+ prog[N+1].pred = NULL;
+ prog[N+1].target = 0; /* FALSE */
+ prog[N-1].target = N;
+ prog[N-1].when_to_branch = false;
+
+ /* Second Pass */
+ for (i = N-1 ; i--; ) {
+ int target = prog[i].target;
+ if (prog[i].when_to_branch == prog[target].when_to_branch)
+ prog[i].target = prog[target].target;
+ }
+
+ /* Third Pass */
+ for (i = 0; i < N; i++) {
+ invert = inverts[i] ^ prog[i].when_to_branch;
+ prog[i].when_to_branch = invert;
+ /* Make sure the program always moves forward */
+ if (WARN_ON(prog[i].target <= i)) {
+ ret = -EINVAL;
+ goto out_free;
+ }
+ }
+
+ return prog;
+out_free:
+ kfree(op_stack);
+ kfree(prog_stack);
+ kfree(inverts);
+ return ERR_PTR(ret);
+}
+
#define DEFINE_COMPARISON_PRED(type) \
static int filter_pred_LT_##type(struct filter_pred *pred, void *event) \
{ \
type *addr = (type *)(event + pred->offset); \
type val = (type)pred->val; \
- int match = (*addr < val); \
- return !!match == !pred->not; \
+ return *addr < val; \
} \
static int filter_pred_LE_##type(struct filter_pred *pred, void *event) \
{ \
type *addr = (type *)(event + pred->offset); \
type val = (type)pred->val; \
- int match = (*addr <= val); \
- return !!match == !pred->not; \
+ return *addr <= val; \
} \
static int filter_pred_GT_##type(struct filter_pred *pred, void *event) \
{ \
type *addr = (type *)(event + pred->offset); \
type val = (type)pred->val; \
- int match = (*addr > val); \
- return !!match == !pred->not; \
+ return *addr > val; \
} \
static int filter_pred_GE_##type(struct filter_pred *pred, void *event) \
{ \
type *addr = (type *)(event + pred->offset); \
type val = (type)pred->val; \
- int match = (*addr >= val); \
- return !!match == !pred->not; \
+ return *addr >= val; \
} \
static int filter_pred_BAND_##type(struct filter_pred *pred, void *event) \
{ \
type *addr = (type *)(event + pred->offset); \
type val = (type)pred->val; \
- int match = !!(*addr & val); \
- return match == !pred->not; \
+ return !!(*addr & val); \
} \
static const filter_pred_fn_t pred_funcs_##type[] = { \
- filter_pred_LT_##type, \
filter_pred_LE_##type, \
- filter_pred_GT_##type, \
+ filter_pred_LT_##type, \
filter_pred_GE_##type, \
+ filter_pred_GT_##type, \
filter_pred_BAND_##type, \
};

@@ -261,44 +704,36 @@ static int filter_pred_strloc(struct filter_pred *pred, void *event)
static int filter_pred_cpu(struct filter_pred *pred, void *event)
{
int cpu, cmp;
- int match = 0;

cpu = raw_smp_processor_id();
cmp = pred->val;

switch (pred->op) {
case OP_EQ:
- match = cpu == cmp;
- break;
+ return cpu == cmp;
+ case OP_NE:
+ return cpu != cmp;
case OP_LT:
- match = cpu < cmp;
- break;
+ return cpu < cmp;
case OP_LE:
- match = cpu <= cmp;
- break;
+ return cpu <= cmp;
case OP_GT:
- match = cpu > cmp;
- break;
+ return cpu > cmp;
case OP_GE:
- match = cpu >= cmp;
- break;
+ return cpu >= cmp;
default:
- break;
+ return 0;
}
-
- return !!match == !pred->not;
}

/* Filter predicate for COMM. */
static int filter_pred_comm(struct filter_pred *pred, void *event)
{
- int cmp, match;
+ int cmp;

cmp = pred->regex.match(current->comm, &pred->regex,
- pred->regex.field_len);
- match = cmp ^ pred->not;
-
- return match;
+ TASK_COMM_LEN);
+ return cmp ^ pred->not;
}

static int filter_pred_none(struct filter_pred *pred, void *event)
@@ -355,6 +790,7 @@ static int regex_match_glob(char *str, struct regex *r, int len __maybe_unused)
return 1;
return 0;
}
+
/**
* filter_parse_regex - parse a basic regex
* @buff: the raw regex
@@ -415,10 +851,9 @@ static void filter_build_regex(struct filter_pred *pred)
struct regex *r = &pred->regex;
char *search;
enum regex_type type = MATCH_FULL;
- int not = 0;

if (pred->op == OP_GLOB) {
- type = filter_parse_regex(r->pattern, r->len, &search, &not);
+ type = filter_parse_regex(r->pattern, r->len, &search, &pred->not);
r->len = strlen(search);
memmove(r->pattern, search, r->len+1);
}
@@ -440,210 +875,32 @@ static void filter_build_regex(struct filter_pred *pred)
r->match = regex_match_glob;
break;
}
-
- pred->not ^= not;
-}
-
-enum move_type {
- MOVE_DOWN,
- MOVE_UP_FROM_LEFT,
- MOVE_UP_FROM_RIGHT
-};
-
-static struct filter_pred *
-get_pred_parent(struct filter_pred *pred, struct filter_pred *preds,
- int index, enum move_type *move)
-{
- if (pred->parent & FILTER_PRED_IS_RIGHT)
- *move = MOVE_UP_FROM_RIGHT;
- else
- *move = MOVE_UP_FROM_LEFT;
- pred = &preds[pred->parent & ~FILTER_PRED_IS_RIGHT];
-
- return pred;
-}
-
-enum walk_return {
- WALK_PRED_ABORT,
- WALK_PRED_PARENT,
- WALK_PRED_DEFAULT,
-};
-
-typedef int (*filter_pred_walkcb_t) (enum move_type move,
- struct filter_pred *pred,
- int *err, void *data);
-
-static int walk_pred_tree(struct filter_pred *preds,
- struct filter_pred *root,
- filter_pred_walkcb_t cb, void *data)
-{
- struct filter_pred *pred = root;
- enum move_type move = MOVE_DOWN;
- int done = 0;
-
- if (!preds)
- return -EINVAL;
-
- do {
- int err = 0, ret;
-
- ret = cb(move, pred, &err, data);
- if (ret == WALK_PRED_ABORT)
- return err;
- if (ret == WALK_PRED_PARENT)
- goto get_parent;
-
- switch (move) {
- case MOVE_DOWN:
- if (pred->left != FILTER_PRED_INVALID) {
- pred = &preds[pred->left];
- continue;
- }
- goto get_parent;
- case MOVE_UP_FROM_LEFT:
- pred = &preds[pred->right];
- move = MOVE_DOWN;
- continue;
- case MOVE_UP_FROM_RIGHT:
- get_parent:
- if (pred == root)
- break;
- pred = get_pred_parent(pred, preds,
- pred->parent,
- &move);
- continue;
- }
- done = 1;
- } while (!done);
-
- /* We are fine. */
- return 0;
-}
-
-/*
- * A series of AND or ORs where found together. Instead of
- * climbing up and down the tree branches, an array of the
- * ops were made in order of checks. We can just move across
- * the array and short circuit if needed.
- */
-static int process_ops(struct filter_pred *preds,
- struct filter_pred *op, void *rec)
-{
- struct filter_pred *pred;
- int match = 0;
- int type;
- int i;
-
- /*
- * Micro-optimization: We set type to true if op
- * is an OR and false otherwise (AND). Then we
- * just need to test if the match is equal to
- * the type, and if it is, we can short circuit the
- * rest of the checks:
- *
- * if ((match && op->op == OP_OR) ||
- * (!match && op->op == OP_AND))
- * return match;
- */
- type = op->op == OP_OR;
-
- for (i = 0; i < op->val; i++) {
- pred = &preds[op->ops[i]];
- if (!WARN_ON_ONCE(!pred->fn))
- match = pred->fn(pred, rec);
- if (!!match == type)
- break;
- }
- /* If not of not match is equal to not of not, then it is a match */
- return !!match == !op->not;
-}
-
-struct filter_match_preds_data {
- struct filter_pred *preds;
- int match;
- void *rec;
-};
-
-static int filter_match_preds_cb(enum move_type move, struct filter_pred *pred,
- int *err, void *data)
-{
- struct filter_match_preds_data *d = data;
-
- *err = 0;
- switch (move) {
- case MOVE_DOWN:
- /* only AND and OR have children */
- if (pred->left != FILTER_PRED_INVALID) {
- /* If ops is set, then it was folded. */
- if (!pred->ops)
- return WALK_PRED_DEFAULT;
- /* We can treat folded ops as a leaf node */
- d->match = process_ops(d->preds, pred, d->rec);
- } else {
- if (!WARN_ON_ONCE(!pred->fn))
- d->match = pred->fn(pred, d->rec);
- }
-
- return WALK_PRED_PARENT;
- case MOVE_UP_FROM_LEFT:
- /*
- * Check for short circuits.
- *
- * Optimization: !!match == (pred->op == OP_OR)
- * is the same as:
- * if ((match && pred->op == OP_OR) ||
- * (!match && pred->op == OP_AND))
- */
- if (!!d->match == (pred->op == OP_OR))
- return WALK_PRED_PARENT;
- break;
- case MOVE_UP_FROM_RIGHT:
- break;
- }
-
- return WALK_PRED_DEFAULT;
}

/* return 1 if event matches, 0 otherwise (discard) */
int filter_match_preds(struct event_filter *filter, void *rec)
{
- struct filter_pred *preds;
- struct filter_pred *root;
- struct filter_match_preds_data data = {
- /* match is currently meaningless */
- .match = -1,
- .rec = rec,
- };
- int n_preds, ret;
+ struct prog_entry *prog;
+ int i;

/* no filter is considered a match */
if (!filter)
return 1;

- n_preds = filter->n_preds;
- if (!n_preds)
+ prog = rcu_dereference_sched(filter->prog);
+ if (!prog)
return 1;

- /*
- * n_preds, root and filter->preds are protect with preemption disabled.
- */
- root = rcu_dereference_sched(filter->root);
- if (!root)
- return 1;
-
- data.preds = preds = rcu_dereference_sched(filter->preds);
- ret = walk_pred_tree(preds, root, filter_match_preds_cb, &data);
- WARN_ON(ret);
- return data.match;
+ for (i = 0; prog[i].pred; i++) {
+ struct filter_pred *pred = prog[i].pred;
+ int match = pred->fn(pred, rec);
+ if (match == prog[i].when_to_branch)
+ i = prog[i].target;
+ }
+ return prog[i].target;
}
EXPORT_SYMBOL_GPL(filter_match_preds);

-static void parse_error(struct filter_parse_state *ps, int err, int pos)
-{
- ps->lasterr = err;
- ps->lasterr_pos = pos;
-}
-
static void remove_filter_string(struct event_filter *filter)
{
if (!filter)
@@ -653,11 +910,11 @@ static void remove_filter_string(struct event_filter *filter)
filter->filter_string = NULL;
}

-static void append_filter_err(struct filter_parse_state *ps,
+static void append_filter_err(struct filter_parse_error *pe,
struct event_filter *filter)
{
struct trace_seq *s;
- int pos = ps->lasterr_pos;
+ int pos = pe->lasterr_pos;
char *buf;
int len;

@@ -671,11 +928,19 @@ static void append_filter_err(struct filter_parse_state *ps,

len = strlen(filter->filter_string);
if (pos > len)
- len = pos;
+ pos = len;
+
+ /* indexing is off by one */
+ if (pos)
+ pos++;

trace_seq_puts(s, filter->filter_string);
- trace_seq_printf(s, "\n%*s", pos, "^");
- trace_seq_printf(s, "\nparse_error: %s\n", err_text[ps->lasterr]);
+ if (pe->lasterr > 0) {
+ trace_seq_printf(s, "\n%*s", pos, "^");
+ trace_seq_printf(s, "\nparse_error: %s\n", err_text[pe->lasterr]);
+ } else {
+ trace_seq_printf(s, "\nError: (%d)\n", pe->lasterr);
+ }
trace_seq_putc(s, 0);
buf = kmemdup_nul(s->buffer, s->seq.len, GFP_KERNEL);
if (buf) {
@@ -715,108 +980,18 @@ void print_subsystem_event_filter(struct event_subsystem *system,
mutex_unlock(&event_mutex);
}

-static int __alloc_pred_stack(struct pred_stack *stack, int n_preds)
-{
- stack->preds = kcalloc(n_preds + 1, sizeof(*stack->preds), GFP_KERNEL);
- if (!stack->preds)
- return -ENOMEM;
- stack->index = n_preds;
- return 0;
-}
-
-static void __free_pred_stack(struct pred_stack *stack)
-{
- kfree(stack->preds);
- stack->index = 0;
-}
-
-static int __push_pred_stack(struct pred_stack *stack,
- struct filter_pred *pred)
-{
- int index = stack->index;
-
- if (WARN_ON(index == 0))
- return -ENOSPC;
-
- stack->preds[--index] = pred;
- stack->index = index;
- return 0;
-}
-
-static struct filter_pred *
-__pop_pred_stack(struct pred_stack *stack)
-{
- struct filter_pred *pred;
- int index = stack->index;
-
- pred = stack->preds[index++];
- if (!pred)
- return NULL;
-
- stack->index = index;
- return pred;
-}
-
-static int filter_set_pred(struct event_filter *filter,
- int idx,
- struct pred_stack *stack,
- struct filter_pred *src)
-{
- struct filter_pred *dest = &filter->preds[idx];
- struct filter_pred *left;
- struct filter_pred *right;
-
- *dest = *src;
- dest->index = idx;
-
- if (dest->op == OP_OR || dest->op == OP_AND) {
- right = __pop_pred_stack(stack);
- left = __pop_pred_stack(stack);
- if (!left || !right)
- return -EINVAL;
- /*
- * If both children can be folded
- * and they are the same op as this op or a leaf,
- * then this op can be folded.
- */
- if (left->index & FILTER_PRED_FOLD &&
- ((left->op == dest->op && !left->not) ||
- left->left == FILTER_PRED_INVALID) &&
- right->index & FILTER_PRED_FOLD &&
- ((right->op == dest->op && !right->not) ||
- right->left == FILTER_PRED_INVALID))
- dest->index |= FILTER_PRED_FOLD;
-
- dest->left = left->index & ~FILTER_PRED_FOLD;
- dest->right = right->index & ~FILTER_PRED_FOLD;
- left->parent = dest->index & ~FILTER_PRED_FOLD;
- right->parent = dest->index | FILTER_PRED_IS_RIGHT;
- } else {
- /*
- * Make dest->left invalid to be used as a quick
- * way to know this is a leaf node.
- */
- dest->left = FILTER_PRED_INVALID;
-
- /* All leafs allow folding the parent ops. */
- dest->index |= FILTER_PRED_FOLD;
- }
-
- return __push_pred_stack(stack, dest);
-}
-
-static void __free_preds(struct event_filter *filter)
+static void free_prog(struct event_filter *filter)
{
+ struct prog_entry *prog;
int i;

- if (filter->preds) {
- for (i = 0; i < filter->n_preds; i++)
- kfree(filter->preds[i].ops);
- kfree(filter->preds);
- filter->preds = NULL;
- }
- filter->a_preds = 0;
- filter->n_preds = 0;
+ prog = rcu_access_pointer(filter->prog);
+ if (!prog)
+ return;
+
+ for (i = 0; prog[i].pred; i++)
+ kfree(prog[i].pred);
+ kfree(prog);
}

static void filter_disable(struct trace_event_file *file)
@@ -834,7 +1009,7 @@ static void __free_filter(struct event_filter *filter)
if (!filter)
return;

- __free_preds(filter);
+ free_prog(filter);
kfree(filter->filter_string);
kfree(filter);
}
@@ -844,30 +1019,6 @@ void free_event_filter(struct event_filter *filter)
__free_filter(filter);
}

-static int __alloc_preds(struct event_filter *filter, int n_preds)
-{
- struct filter_pred *pred;
- int i;
-
- if (filter->preds)
- __free_preds(filter);
-
- filter->preds = kcalloc(n_preds, sizeof(*filter->preds), GFP_KERNEL);
-
- if (!filter->preds)
- return -ENOMEM;
-
- filter->a_preds = n_preds;
- filter->n_preds = 0;
-
- for (i = 0; i < n_preds; i++) {
- pred = &filter->preds[i];
- pred->fn = filter_pred_none;
- }
-
- return 0;
-}
-
static inline void __remove_filter(struct trace_event_file *file)
{
filter_disable(file);
@@ -898,812 +1049,466 @@ static void filter_free_subsystem_filters(struct trace_subsystem_dir *dir,
struct trace_event_file *file;

list_for_each_entry(file, &tr->events, list) {
- if (file->system != dir)
- continue;
- __free_subsystem_filter(file);
- }
-}
-
-static int filter_add_pred(struct filter_parse_state *ps,
- struct event_filter *filter,
- struct filter_pred *pred,
- struct pred_stack *stack)
-{
- int err;
-
- if (WARN_ON(filter->n_preds == filter->a_preds)) {
- parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
- return -ENOSPC;
- }
-
- err = filter_set_pred(filter, filter->n_preds, stack, pred);
- if (err)
- return err;
-
- filter->n_preds++;
-
- return 0;
-}
-
-int filter_assign_type(const char *type)
-{
- if (strstr(type, "__data_loc") && strstr(type, "char"))
- return FILTER_DYN_STRING;
-
- if (strchr(type, '[') && strstr(type, "char"))
- return FILTER_STATIC_STRING;
-
- return FILTER_OTHER;
-}
-
-static bool is_legal_op(struct ftrace_event_field *field, enum filter_op_ids op)
-{
- if (is_string_field(field) &&
- (op != OP_EQ && op != OP_NE && op != OP_GLOB))
- return false;
- if (!is_string_field(field) && op == OP_GLOB)
- return false;
-
- return true;
-}
-
-static filter_pred_fn_t select_comparison_fn(enum filter_op_ids op,
- int field_size, int field_is_signed)
-{
- filter_pred_fn_t fn = NULL;
- int pred_func_index = -1;
-
- switch (op) {
- case OP_EQ:
- case OP_NE:
- break;
- default:
- if (WARN_ON_ONCE(op < PRED_FUNC_START))
- return NULL;
- pred_func_index = op - PRED_FUNC_START;
- if (WARN_ON_ONCE(pred_func_index > PRED_FUNC_MAX))
- return NULL;
- }
-
- switch (field_size) {
- case 8:
- if (pred_func_index < 0)
- fn = filter_pred_64;
- else if (field_is_signed)
- fn = pred_funcs_s64[pred_func_index];
- else
- fn = pred_funcs_u64[pred_func_index];
- break;
- case 4:
- if (pred_func_index < 0)
- fn = filter_pred_32;
- else if (field_is_signed)
- fn = pred_funcs_s32[pred_func_index];
- else
- fn = pred_funcs_u32[pred_func_index];
- break;
- case 2:
- if (pred_func_index < 0)
- fn = filter_pred_16;
- else if (field_is_signed)
- fn = pred_funcs_s16[pred_func_index];
- else
- fn = pred_funcs_u16[pred_func_index];
- break;
- case 1:
- if (pred_func_index < 0)
- fn = filter_pred_8;
- else if (field_is_signed)
- fn = pred_funcs_s8[pred_func_index];
- else
- fn = pred_funcs_u8[pred_func_index];
- break;
- }
-
- return fn;
-}
-
-static int init_pred(struct filter_parse_state *ps,
- struct ftrace_event_field *field,
- struct filter_pred *pred)
-
-{
- filter_pred_fn_t fn = filter_pred_none;
- unsigned long long val;
- int ret;
-
- pred->offset = field->offset;
-
- if (!is_legal_op(field, pred->op)) {
- parse_error(ps, FILT_ERR_ILLEGAL_FIELD_OP, 0);
- return -EINVAL;
- }
-
- if (field->filter_type == FILTER_COMM) {
- filter_build_regex(pred);
- fn = filter_pred_comm;
- pred->regex.field_len = TASK_COMM_LEN;
- } else if (is_string_field(field)) {
- filter_build_regex(pred);
-
- if (field->filter_type == FILTER_STATIC_STRING) {
- fn = filter_pred_string;
- pred->regex.field_len = field->size;
- } else if (field->filter_type == FILTER_DYN_STRING)
- fn = filter_pred_strloc;
- else
- fn = filter_pred_pchar;
- } else if (is_function_field(field)) {
- if (strcmp(field->name, "ip")) {
- parse_error(ps, FILT_ERR_IP_FIELD_ONLY, 0);
- return -EINVAL;
- }
- } else {
- if (field->is_signed)
- ret = kstrtoll(pred->regex.pattern, 0, &val);
- else
- ret = kstrtoull(pred->regex.pattern, 0, &val);
- if (ret) {
- parse_error(ps, FILT_ERR_ILLEGAL_INTVAL, 0);
- return -EINVAL;
- }
- pred->val = val;
-
- if (field->filter_type == FILTER_CPU)
- fn = filter_pred_cpu;
- else
- fn = select_comparison_fn(pred->op, field->size,
- field->is_signed);
- if (!fn) {
- parse_error(ps, FILT_ERR_INVALID_OP, 0);
- return -EINVAL;
- }
- }
-
- if (pred->op == OP_NE)
- pred->not ^= 1;
-
- pred->fn = fn;
- return 0;
-}
-
-static void parse_init(struct filter_parse_state *ps,
- struct filter_op *ops,
- char *infix_string)
-{
- memset(ps, '\0', sizeof(*ps));
-
- ps->infix.string = infix_string;
- ps->infix.cnt = strlen(infix_string);
- ps->ops = ops;
-
- INIT_LIST_HEAD(&ps->opstack);
- INIT_LIST_HEAD(&ps->postfix);
-}
-
-static char infix_next(struct filter_parse_state *ps)
-{
- if (!ps->infix.cnt)
- return 0;
-
- ps->infix.cnt--;
-
- return ps->infix.string[ps->infix.tail++];
-}
-
-static char infix_peek(struct filter_parse_state *ps)
-{
- if (ps->infix.tail == strlen(ps->infix.string))
- return 0;
-
- return ps->infix.string[ps->infix.tail];
-}
-
-static void infix_advance(struct filter_parse_state *ps)
-{
- if (!ps->infix.cnt)
- return;
-
- ps->infix.cnt--;
- ps->infix.tail++;
-}
-
-static inline int is_precedence_lower(struct filter_parse_state *ps,
- int a, int b)
-{
- return ps->ops[a].precedence < ps->ops[b].precedence;
-}
-
-static inline int is_op_char(struct filter_parse_state *ps, char c)
-{
- int i;
-
- for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
- if (ps->ops[i].string[0] == c)
- return 1;
- }
-
- return 0;
-}
-
-static int infix_get_op(struct filter_parse_state *ps, char firstc)
-{
- char nextc = infix_peek(ps);
- char opstr[3];
- int i;
-
- opstr[0] = firstc;
- opstr[1] = nextc;
- opstr[2] = '\0';
-
- for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
- if (!strcmp(opstr, ps->ops[i].string)) {
- infix_advance(ps);
- return ps->ops[i].id;
- }
- }
-
- opstr[1] = '\0';
-
- for (i = 0; strcmp(ps->ops[i].string, "OP_NONE"); i++) {
- if (!strcmp(opstr, ps->ops[i].string))
- return ps->ops[i].id;
- }
-
- return OP_NONE;
-}
-
-static inline void clear_operand_string(struct filter_parse_state *ps)
-{
- memset(ps->operand.string, '\0', MAX_FILTER_STR_VAL);
- ps->operand.tail = 0;
-}
-
-static inline int append_operand_char(struct filter_parse_state *ps, char c)
-{
- if (ps->operand.tail == MAX_FILTER_STR_VAL - 1)
- return -EINVAL;
-
- ps->operand.string[ps->operand.tail++] = c;
-
- return 0;
-}
-
-static int filter_opstack_push(struct filter_parse_state *ps,
- enum filter_op_ids op)
-{
- struct opstack_op *opstack_op;
-
- opstack_op = kmalloc(sizeof(*opstack_op), GFP_KERNEL);
- if (!opstack_op)
- return -ENOMEM;
-
- opstack_op->op = op;
- list_add(&opstack_op->list, &ps->opstack);
-
- return 0;
-}
-
-static int filter_opstack_empty(struct filter_parse_state *ps)
-{
- return list_empty(&ps->opstack);
-}
-
-static int filter_opstack_top(struct filter_parse_state *ps)
-{
- struct opstack_op *opstack_op;
-
- if (filter_opstack_empty(ps))
- return OP_NONE;
-
- opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
-
- return opstack_op->op;
-}
-
-static int filter_opstack_pop(struct filter_parse_state *ps)
-{
- struct opstack_op *opstack_op;
- enum filter_op_ids op;
-
- if (filter_opstack_empty(ps))
- return OP_NONE;
-
- opstack_op = list_first_entry(&ps->opstack, struct opstack_op, list);
- op = opstack_op->op;
- list_del(&opstack_op->list);
-
- kfree(opstack_op);
-
- return op;
-}
-
-static void filter_opstack_clear(struct filter_parse_state *ps)
-{
- while (!filter_opstack_empty(ps))
- filter_opstack_pop(ps);
-}
-
-static char *curr_operand(struct filter_parse_state *ps)
-{
- return ps->operand.string;
-}
-
-static int postfix_append_operand(struct filter_parse_state *ps, char *operand)
-{
- struct postfix_elt *elt;
-
- elt = kmalloc(sizeof(*elt), GFP_KERNEL);
- if (!elt)
- return -ENOMEM;
-
- elt->op = OP_NONE;
- elt->operand = kstrdup(operand, GFP_KERNEL);
- if (!elt->operand) {
- kfree(elt);
- return -ENOMEM;
- }
-
- list_add_tail(&elt->list, &ps->postfix);
-
- return 0;
-}
-
-static int postfix_append_op(struct filter_parse_state *ps, enum filter_op_ids op)
-{
- struct postfix_elt *elt;
-
- elt = kmalloc(sizeof(*elt), GFP_KERNEL);
- if (!elt)
- return -ENOMEM;
-
- elt->op = op;
- elt->operand = NULL;
-
- list_add_tail(&elt->list, &ps->postfix);
-
- return 0;
-}
-
-static void postfix_clear(struct filter_parse_state *ps)
-{
- struct postfix_elt *elt;
-
- while (!list_empty(&ps->postfix)) {
- elt = list_first_entry(&ps->postfix, struct postfix_elt, list);
- list_del(&elt->list);
- kfree(elt->operand);
- kfree(elt);
- }
-}
-
-static int filter_parse(struct filter_parse_state *ps)
-{
- enum filter_op_ids op, top_op;
- int in_string = 0;
- char ch;
-
- while ((ch = infix_next(ps))) {
- if (ch == '"') {
- in_string ^= 1;
- continue;
- }
-
- if (in_string)
- goto parse_operand;
-
- if (isspace(ch))
- continue;
-
- if (is_op_char(ps, ch)) {
- op = infix_get_op(ps, ch);
- if (op == OP_NONE) {
- parse_error(ps, FILT_ERR_INVALID_OP, 0);
- return -EINVAL;
- }
-
- if (strlen(curr_operand(ps))) {
- postfix_append_operand(ps, curr_operand(ps));
- clear_operand_string(ps);
- }
-
- while (!filter_opstack_empty(ps)) {
- top_op = filter_opstack_top(ps);
- if (!is_precedence_lower(ps, top_op, op)) {
- top_op = filter_opstack_pop(ps);
- postfix_append_op(ps, top_op);
- continue;
- }
- break;
- }
-
- filter_opstack_push(ps, op);
- continue;
- }
-
- if (ch == '(') {
- filter_opstack_push(ps, OP_OPEN_PAREN);
- continue;
- }
-
- if (ch == ')') {
- if (strlen(curr_operand(ps))) {
- postfix_append_operand(ps, curr_operand(ps));
- clear_operand_string(ps);
- }
-
- top_op = filter_opstack_pop(ps);
- while (top_op != OP_NONE) {
- if (top_op == OP_OPEN_PAREN)
- break;
- postfix_append_op(ps, top_op);
- top_op = filter_opstack_pop(ps);
- }
- if (top_op == OP_NONE) {
- parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
- return -EINVAL;
- }
+ if (file->system != dir)
continue;
- }
-parse_operand:
- if (append_operand_char(ps, ch)) {
- parse_error(ps, FILT_ERR_OPERAND_TOO_LONG, 0);
- return -EINVAL;
- }
+ __free_subsystem_filter(file);
}
+}

- if (strlen(curr_operand(ps)))
- postfix_append_operand(ps, curr_operand(ps));
+int filter_assign_type(const char *type)
+{
+ if (strstr(type, "__data_loc") && strstr(type, "char"))
+ return FILTER_DYN_STRING;

- while (!filter_opstack_empty(ps)) {
- top_op = filter_opstack_pop(ps);
- if (top_op == OP_NONE)
- break;
- if (top_op == OP_OPEN_PAREN) {
- parse_error(ps, FILT_ERR_UNBALANCED_PAREN, 0);
- return -EINVAL;
- }
- postfix_append_op(ps, top_op);
- }
+ if (strchr(type, '[') && strstr(type, "char"))
+ return FILTER_STATIC_STRING;

- return 0;
+ return FILTER_OTHER;
}

-static struct filter_pred *create_pred(struct filter_parse_state *ps,
- struct trace_event_call *call,
- enum filter_op_ids op,
- char *operand1, char *operand2)
+static filter_pred_fn_t select_comparison_fn(enum filter_op_ids op,
+ int field_size, int field_is_signed)
{
- struct ftrace_event_field *field;
- static struct filter_pred pred;
-
- memset(&pred, 0, sizeof(pred));
- pred.op = op;
-
- if (op == OP_AND || op == OP_OR)
- return &pred;
+ filter_pred_fn_t fn = NULL;
+ int pred_func_index = -1;

- if (!operand1 || !operand2) {
- parse_error(ps, FILT_ERR_MISSING_FIELD, 0);
- return NULL;
+ switch (op) {
+ case OP_EQ:
+ case OP_NE:
+ break;
+ default:
+ if (WARN_ON_ONCE(op < PRED_FUNC_START))
+ return NULL;
+ pred_func_index = op - PRED_FUNC_START;
+ if (WARN_ON_ONCE(pred_func_index > PRED_FUNC_MAX))
+ return NULL;
}

- field = trace_find_event_field(call, operand1);
- if (!field) {
- parse_error(ps, FILT_ERR_FIELD_NOT_FOUND, 0);
- return NULL;
+ switch (field_size) {
+ case 8:
+ if (pred_func_index < 0)
+ fn = filter_pred_64;
+ else if (field_is_signed)
+ fn = pred_funcs_s64[pred_func_index];
+ else
+ fn = pred_funcs_u64[pred_func_index];
+ break;
+ case 4:
+ if (pred_func_index < 0)
+ fn = filter_pred_32;
+ else if (field_is_signed)
+ fn = pred_funcs_s32[pred_func_index];
+ else
+ fn = pred_funcs_u32[pred_func_index];
+ break;
+ case 2:
+ if (pred_func_index < 0)
+ fn = filter_pred_16;
+ else if (field_is_signed)
+ fn = pred_funcs_s16[pred_func_index];
+ else
+ fn = pred_funcs_u16[pred_func_index];
+ break;
+ case 1:
+ if (pred_func_index < 0)
+ fn = filter_pred_8;
+ else if (field_is_signed)
+ fn = pred_funcs_s8[pred_func_index];
+ else
+ fn = pred_funcs_u8[pred_func_index];
+ break;
}

- strcpy(pred.regex.pattern, operand2);
- pred.regex.len = strlen(pred.regex.pattern);
- pred.field = field;
- return init_pred(ps, field, &pred) ? NULL : &pred;
+ return fn;
}

-static int check_preds(struct filter_parse_state *ps)
+/* Called when a predicate is encountered by predicate_parse() */
+static int parse_pred(const char *str, void *data,
+ int pos, struct filter_parse_error *pe,
+ struct filter_pred **pred_ptr)
{
- int n_normal_preds = 0, n_logical_preds = 0;
- struct postfix_elt *elt;
- int cnt = 0;
+ struct trace_event_call *call = data;
+ struct ftrace_event_field *field;
+ struct filter_pred *pred = NULL;
+ char num_buf[24]; /* Big enough to hold an address */
+ char *field_name;
+ char q;
+ u64 val;
+ int len;
+ int ret;
+ int op;
+ int s;
+ int i = 0;

- list_for_each_entry(elt, &ps->postfix, list) {
- if (elt->op == OP_NONE) {
- cnt++;
- continue;
- }
+ /* First find the field to associate to */
+ while (isspace(str[i]))
+ i++;
+ s = i;

- if (elt->op == OP_AND || elt->op == OP_OR) {
- n_logical_preds++;
- cnt--;
- continue;
- }
- if (elt->op != OP_NOT)
- cnt--;
- n_normal_preds++;
- /* all ops should have operands */
- if (cnt < 0)
- break;
- }
+ while (isalnum(str[i]) || str[i] == '_')
+ i++;
+
+ len = i - s;
+
+ if (!len)
+ return -1;
+
+ field_name = kmemdup_nul(str + s, len, GFP_KERNEL);
+ if (!field_name)
+ return -ENOMEM;
+
+ /* Make sure that the field exists */

- if (cnt != 1 || !n_normal_preds || n_logical_preds >= n_normal_preds) {
- parse_error(ps, FILT_ERR_INVALID_FILTER, 0);
+ field = trace_find_event_field(call, field_name);
+ kfree(field_name);
+ if (!field) {
+ parse_error(pe, FILT_ERR_FIELD_NOT_FOUND, pos + i);
return -EINVAL;
}

- return 0;
-}
+ while (isspace(str[i]))
+ i++;

-static int count_preds(struct filter_parse_state *ps)
-{
- struct postfix_elt *elt;
- int n_preds = 0;
+ /* Make sure this op is supported */
+ for (op = 0; ops[op]; op++) {
+ /* This is why '<=' must come before '<' in ops[] */
+ if (strncmp(str + i, ops[op], strlen(ops[op])) == 0)
+ break;
+ }

- list_for_each_entry(elt, &ps->postfix, list) {
- if (elt->op == OP_NONE)
- continue;
- n_preds++;
+ if (!ops[op]) {
+ parse_error(pe, FILT_ERR_INVALID_OP, pos + i);
+ goto err_free;
}

- return n_preds;
-}
+ i += strlen(ops[op]);

-struct check_pred_data {
- int count;
- int max;
-};
+ while (isspace(str[i]))
+ i++;

-static int check_pred_tree_cb(enum move_type move, struct filter_pred *pred,
- int *err, void *data)
-{
- struct check_pred_data *d = data;
+ s = i;

- if (WARN_ON(d->count++ > d->max)) {
- *err = -EINVAL;
- return WALK_PRED_ABORT;
- }
- return WALK_PRED_DEFAULT;
-}
+ pred = kzalloc(sizeof(*pred), GFP_KERNEL);
+ if (!pred)
+ return -ENOMEM;

-/*
- * The tree is walked at filtering of an event. If the tree is not correctly
- * built, it may cause an infinite loop. Check here that the tree does
- * indeed terminate.
- */
-static int check_pred_tree(struct event_filter *filter,
- struct filter_pred *root)
-{
- struct check_pred_data data = {
+ pred->field = field;
+ pred->offset = field->offset;
+ pred->op = op;
+
+ if (ftrace_event_is_function(call)) {
/*
- * The max that we can hit a node is three times.
- * Once going down, once coming up from left, and
- * once coming up from right. This is more than enough
- * since leafs are only hit a single time.
+ * Perf does things different with function events.
+ * It only allows an "ip" field, and expects a string.
+ * But the string does not need to be surrounded by quotes.
+ * If it is a string, the assigned function as a nop,
+ * (perf doesn't use it) and grab everything.
*/
- .max = 3 * filter->n_preds,
- .count = 0,
- };
+ if (strcmp(field->name, "ip") != 0) {
+ parse_error(pe, FILT_ERR_IP_FIELD_ONLY, pos + i);
+ goto err_free;
+ }
+ pred->fn = filter_pred_none;
+
+ /*
+ * Quotes are not required, but if they exist then we need
+ * to read them till we hit a matching one.
+ */
+ if (str[i] == '\'' || str[i] == '"')
+ q = str[i];
+ else
+ q = 0;
+
+ for (i++; str[i]; i++) {
+ if (q && str[i] == q)
+ break;
+ if (!q && (str[i] == ')' || str[i] == '&' ||
+ str[i] == '|'))
+ break;
+ }
+ /* Skip quotes */
+ if (q)
+ s++;
+ len = i - s;
+ if (len >= MAX_FILTER_STR_VAL) {
+ parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
+ goto err_free;
+ }

- return walk_pred_tree(filter->preds, root,
- check_pred_tree_cb, &data);
-}
+ pred->regex.len = len;
+ strncpy(pred->regex.pattern, str + s, len);
+ pred->regex.pattern[len] = 0;
+
+ /* This is either a string, or an integer */
+ } else if (str[i] == '\'' || str[i] == '"') {
+ char q = str[i];
+
+ /* Make sure the op is OK for strings */
+ switch (op) {
+ case OP_NE:
+ pred->not = 1;
+ /* Fall through */
+ case OP_GLOB:
+ case OP_EQ:
+ break;
+ default:
+ parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i);
+ goto err_free;
+ }

-static int count_leafs_cb(enum move_type move, struct filter_pred *pred,
- int *err, void *data)
-{
- int *count = data;
+ /* Make sure the field is OK for strings */
+ if (!is_string_field(field)) {
+ parse_error(pe, FILT_ERR_EXPECT_DIGIT, pos + i);
+ goto err_free;
+ }

- if ((move == MOVE_DOWN) &&
- (pred->left == FILTER_PRED_INVALID))
- (*count)++;
+ for (i++; str[i]; i++) {
+ if (str[i] == q)
+ break;
+ }
+ if (!str[i]) {
+ parse_error(pe, FILT_ERR_MISSING_QUOTE, pos + i);
+ goto err_free;
+ }

- return WALK_PRED_DEFAULT;
-}
+ /* Skip quotes */
+ s++;
+ len = i - s;
+ if (len >= MAX_FILTER_STR_VAL) {
+ parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
+ goto err_free;
+ }

-static int count_leafs(struct filter_pred *preds, struct filter_pred *root)
-{
- int count = 0, ret;
+ pred->regex.len = len;
+ strncpy(pred->regex.pattern, str + s, len);
+ pred->regex.pattern[len] = 0;

- ret = walk_pred_tree(preds, root, count_leafs_cb, &count);
- WARN_ON(ret);
- return count;
-}
+ filter_build_regex(pred);

-struct fold_pred_data {
- struct filter_pred *root;
- int count;
- int children;
-};
+ if (field->filter_type == FILTER_COMM) {
+ pred->fn = filter_pred_comm;

-static int fold_pred_cb(enum move_type move, struct filter_pred *pred,
- int *err, void *data)
-{
- struct fold_pred_data *d = data;
- struct filter_pred *root = d->root;
+ } else if (field->filter_type == FILTER_STATIC_STRING) {
+ pred->fn = filter_pred_string;
+ pred->regex.field_len = field->size;

- if (move != MOVE_DOWN)
- return WALK_PRED_DEFAULT;
- if (pred->left != FILTER_PRED_INVALID)
- return WALK_PRED_DEFAULT;
+ } else if (field->filter_type == FILTER_DYN_STRING)
+ pred->fn = filter_pred_strloc;
+ else
+ pred->fn = filter_pred_pchar;
+ /* go past the last quote */
+ i++;

- if (WARN_ON(d->count == d->children)) {
- *err = -EINVAL;
- return WALK_PRED_ABORT;
- }
+ } else if (isdigit(str[i])) {

- pred->index &= ~FILTER_PRED_FOLD;
- root->ops[d->count++] = pred->index;
- return WALK_PRED_DEFAULT;
-}
+ /* Make sure the field is not a string */
+ if (is_string_field(field)) {
+ parse_error(pe, FILT_ERR_EXPECT_STRING, pos + i);
+ goto err_free;
+ }

-static int fold_pred(struct filter_pred *preds, struct filter_pred *root)
-{
- struct fold_pred_data data = {
- .root = root,
- .count = 0,
- };
- int children;
+ if (op == OP_GLOB) {
+ parse_error(pe, FILT_ERR_ILLEGAL_FIELD_OP, pos + i);
+ goto err_free;
+ }

- /* No need to keep the fold flag */
- root->index &= ~FILTER_PRED_FOLD;
+ /* We allow 0xDEADBEEF */
+ while (isalnum(str[i]))
+ i++;

- /* If the root is a leaf then do nothing */
- if (root->left == FILTER_PRED_INVALID)
- return 0;
+ len = i - s;
+ /* 0xfeedfacedeadbeef is 18 chars max */
+ if (len >= sizeof(num_buf)) {
+ parse_error(pe, FILT_ERR_OPERAND_TOO_LONG, pos + i);
+ goto err_free;
+ }

- /* count the children */
- children = count_leafs(preds, &preds[root->left]);
- children += count_leafs(preds, &preds[root->right]);
+ strncpy(num_buf, str + s, len);
+ num_buf[len] = 0;

- root->ops = kcalloc(children, sizeof(*root->ops), GFP_KERNEL);
- if (!root->ops)
- return -ENOMEM;
+ /* Make sure it is a value */
+ if (field->is_signed)
+ ret = kstrtoll(num_buf, 0, &val);
+ else
+ ret = kstrtoull(num_buf, 0, &val);
+ if (ret) {
+ parse_error(pe, FILT_ERR_ILLEGAL_INTVAL, pos + s);
+ goto err_free;
+ }

- root->val = children;
- data.children = children;
- return walk_pred_tree(preds, root, fold_pred_cb, &data);
-}
+ pred->val = val;

-static int fold_pred_tree_cb(enum move_type move, struct filter_pred *pred,
- int *err, void *data)
-{
- struct filter_pred *preds = data;
+ if (field->filter_type == FILTER_CPU)
+ pred->fn = filter_pred_cpu;
+ else {
+ pred->fn = select_comparison_fn(pred->op, field->size,
+ field->is_signed);
+ if (pred->op == OP_NE)
+ pred->not = 1;
+ }

- if (move != MOVE_DOWN)
- return WALK_PRED_DEFAULT;
- if (!(pred->index & FILTER_PRED_FOLD))
- return WALK_PRED_DEFAULT;
+ } else {
+ parse_error(pe, FILT_ERR_INVALID_VALUE, pos + i);
+ goto err_free;
+ }

- *err = fold_pred(preds, pred);
- if (*err)
- return WALK_PRED_ABORT;
+ *pred_ptr = pred;
+ return i;

- /* eveyrhing below is folded, continue with parent */
- return WALK_PRED_PARENT;
+err_free:
+ kfree(pred);
+ return -EINVAL;
}

+enum {
+ TOO_MANY_CLOSE = -1,
+ TOO_MANY_OPEN = -2,
+ MISSING_QUOTE = -3,
+};
+
/*
- * To optimize the processing of the ops, if we have several "ors" or
- * "ands" together, we can put them in an array and process them all
- * together speeding up the filter logic.
+ * Read the filter string once to calculate the number of predicates
+ * as well as how deep the parentheses go.
+ *
+ * Returns:
+ * 0 - everything is fine (err is undefined)
+ * -1 - too many ')'
+ * -2 - too many '('
+ * -3 - No matching quote
*/
-static int fold_pred_tree(struct event_filter *filter,
- struct filter_pred *root)
-{
- return walk_pred_tree(filter->preds, root, fold_pred_tree_cb,
- filter->preds);
-}
-
-static int replace_preds(struct trace_event_call *call,
- struct event_filter *filter,
- struct filter_parse_state *ps,
- bool dry_run)
-{
- char *operand1 = NULL, *operand2 = NULL;
- struct filter_pred *pred;
- struct filter_pred *root;
- struct postfix_elt *elt;
- struct pred_stack stack = { }; /* init to NULL */
- int err;
- int n_preds = 0;
-
- n_preds = count_preds(ps);
- if (n_preds >= MAX_FILTER_PRED) {
- parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
- return -ENOSPC;
- }
-
- err = check_preds(ps);
- if (err)
- return err;
+static int calc_stack(const char *str, int *parens, int *preds, int *err)
+{
+ bool is_pred = false;
+ int nr_preds = 0;
+ int open = 1; /* Count the expression as "(E)" */
+ int last_quote = 0;
+ int max_open = 1;
+ int quote = 0;
+ int i;

- if (!dry_run) {
- err = __alloc_pred_stack(&stack, n_preds);
- if (err)
- return err;
- err = __alloc_preds(filter, n_preds);
- if (err)
- goto fail;
- }
+ *err = 0;

- n_preds = 0;
- list_for_each_entry(elt, &ps->postfix, list) {
- if (elt->op == OP_NONE) {
- if (!operand1)
- operand1 = elt->operand;
- else if (!operand2)
- operand2 = elt->operand;
- else {
- parse_error(ps, FILT_ERR_TOO_MANY_OPERANDS, 0);
- err = -EINVAL;
- goto fail;
- }
+ for (i = 0; str[i]; i++) {
+ if (isspace(str[i]))
+ continue;
+ if (quote) {
+ if (str[i] == quote)
+ quote = 0;
continue;
}

- if (elt->op == OP_NOT) {
- if (!n_preds || operand1 || operand2) {
- parse_error(ps, FILT_ERR_ILLEGAL_NOT_OP, 0);
- err = -EINVAL;
- goto fail;
+ switch (str[i]) {
+ case '\'':
+ case '"':
+ quote = str[i];
+ last_quote = i;
+ break;
+ case '|':
+ case '&':
+ if (str[i+1] != str[i])
+ break;
+ is_pred = false;
+ continue;
+ case '(':
+ is_pred = false;
+ open++;
+ if (open > max_open)
+ max_open = open;
+ continue;
+ case ')':
+ is_pred = false;
+ if (open == 1) {
+ *err = i;
+ return TOO_MANY_CLOSE;
}
- if (!dry_run)
- filter->preds[n_preds - 1].not ^= 1;
+ open--;
continue;
}
-
- if (WARN_ON(n_preds++ == MAX_FILTER_PRED)) {
- parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
- err = -ENOSPC;
- goto fail;
+ if (!is_pred) {
+ nr_preds++;
+ is_pred = true;
}
+ }

- pred = create_pred(ps, call, elt->op, operand1, operand2);
- if (!pred) {
- err = -EINVAL;
- goto fail;
- }
+ if (quote) {
+ *err = last_quote;
+ return MISSING_QUOTE;
+ }

- if (!dry_run) {
- err = filter_add_pred(ps, filter, pred, &stack);
- if (err)
- goto fail;
- }
+ if (open != 1) {
+ int level = open;

- operand1 = operand2 = NULL;
+ /* find the bad open */
+ for (i--; i; i--) {
+ if (quote) {
+ if (str[i] == quote)
+ quote = 0;
+ continue;
+ }
+ switch (str[i]) {
+ case '(':
+ if (level == open) {
+ *err = i;
+ return TOO_MANY_OPEN;
+ }
+ level--;
+ break;
+ case ')':
+ level++;
+ break;
+ case '\'':
+ case '"':
+ quote = str[i];
+ break;
+ }
+ }
+ /* First character is the '(' with missing ')' */
+ *err = 0;
+ return TOO_MANY_OPEN;
}

- if (!dry_run) {
- /* We should have one item left on the stack */
- pred = __pop_pred_stack(&stack);
- if (!pred)
- return -EINVAL;
- /* This item is where we start from in matching */
- root = pred;
- /* Make sure the stack is empty */
- pred = __pop_pred_stack(&stack);
- if (WARN_ON(pred)) {
- err = -EINVAL;
- filter->root = NULL;
- goto fail;
+ /* Set the size of the required stacks */
+ *parens = max_open;
+ *preds = nr_preds;
+ return 0;
+}
+
+static int process_preds(struct trace_event_call *call,
+ const char *filter_string,
+ struct event_filter *filter,
+ struct filter_parse_error *pe)
+{
+ struct prog_entry *prog;
+ int nr_parens;
+ int nr_preds;
+ int index;
+ int ret;
+
+ ret = calc_stack(filter_string, &nr_parens, &nr_preds, &index);
+ if (ret < 0) {
+ switch (ret) {
+ case MISSING_QUOTE:
+ parse_error(pe, FILT_ERR_MISSING_QUOTE, index);
+ break;
+ case TOO_MANY_OPEN:
+ parse_error(pe, FILT_ERR_TOO_MANY_OPEN, index);
+ break;
+ default:
+ parse_error(pe, FILT_ERR_TOO_MANY_CLOSE, index);
}
- err = check_pred_tree(filter, root);
- if (err)
- goto fail;
-
- /* Optimize the tree */
- err = fold_pred_tree(filter, root);
- if (err)
- goto fail;
-
- /* We don't set root until we know it works */
- barrier();
- filter->root = root;
+ return ret;
}

- err = 0;
-fail:
- __free_pred_stack(&stack);
- return err;
+ if (!nr_preds) {
+ prog = NULL;
+ } else {
+ prog = predicate_parse(filter_string, nr_parens, nr_preds,
+ parse_pred, call, pe);
+ if (IS_ERR(prog))
+ return PTR_ERR(prog);
+ }
+ rcu_assign_pointer(filter->prog, prog);
+ return 0;
}

static inline void event_set_filtered_flag(struct trace_event_file *file)
@@ -1753,9 +1558,9 @@ struct filter_list {
struct event_filter *filter;
};

-static int replace_system_preds(struct trace_subsystem_dir *dir,
+static int process_system_preds(struct trace_subsystem_dir *dir,
struct trace_array *tr,
- struct filter_parse_state *ps,
+ struct filter_parse_error *pe,
char *filter_string)
{
struct trace_event_file *file;
@@ -1766,29 +1571,11 @@ static int replace_system_preds(struct trace_subsystem_dir *dir,
bool fail = true;
int err;

- list_for_each_entry(file, &tr->events, list) {
- if (file->system != dir)
- continue;
-
- /*
- * Try to see if the filter can be applied
- * (filter arg is ignored on dry_run)
- */
- err = replace_preds(file->event_call, NULL, ps, true);
- if (err)
- event_set_no_set_filter_flag(file);
- else
- event_clear_no_set_filter_flag(file);
- }
-
list_for_each_entry(file, &tr->events, list) {

if (file->system != dir)
continue;

- if (event_no_set_filter_flag(file))
- continue;
-
filter = kzalloc(sizeof(*filter), GFP_KERNEL);
if (!filter)
goto fail_mem;
@@ -1797,11 +1584,11 @@ static int replace_system_preds(struct trace_subsystem_dir *dir,
if (!filter->filter_string)
goto fail_mem;

- err = replace_preds(file->event_call, filter, ps, false);
+ err = process_preds(file->event_call, filter_string, filter, pe);
if (err) {
filter_disable(file);
- parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
- append_filter_err(ps, filter);
+ parse_error(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0);
+ append_filter_err(pe, filter);
} else
event_set_filtered_flag(file);

@@ -1843,7 +1630,7 @@ static int replace_system_preds(struct trace_subsystem_dir *dir,
list_del(&filter_item->list);
kfree(filter_item);
}
- parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
+ parse_error(pe, FILT_ERR_BAD_SUBSYS_FILTER, 0);
return -EINVAL;
fail_mem:
kfree(filter);
@@ -1859,16 +1646,16 @@ static int replace_system_preds(struct trace_subsystem_dir *dir,
}

static int create_filter_start(char *filter_string, bool set_str,
- struct filter_parse_state **psp,
+ struct filter_parse_error **pse,
struct event_filter **filterp)
{
struct event_filter *filter;
- struct filter_parse_state *ps = NULL;
+ struct filter_parse_error *pe = NULL;
int err = 0;

- WARN_ON_ONCE(*psp || *filterp);
+ if (WARN_ON_ONCE(*pse || *filterp))
+ return -EINVAL;

- /* allocate everything, and if any fails, free all and fail */
filter = kzalloc(sizeof(*filter), GFP_KERNEL);
if (filter && set_str) {
filter->filter_string = kstrdup(filter_string, GFP_KERNEL);
@@ -1876,32 +1663,24 @@ static int create_filter_start(char *filter_string, bool set_str,
err = -ENOMEM;
}

- ps = kzalloc(sizeof(*ps), GFP_KERNEL);
+ pe = kzalloc(sizeof(*pe), GFP_KERNEL);

- if (!filter || !ps || err) {
- kfree(ps);
+ if (!filter || !pe || err) {
+ kfree(pe);
__free_filter(filter);
return -ENOMEM;
}

/* we're committed to creating a new filter */
*filterp = filter;
- *psp = ps;
+ *pse = pe;

- parse_init(ps, filter_ops, filter_string);
- err = filter_parse(ps);
- if (err && set_str)
- append_filter_err(ps, filter);
- return err;
+ return 0;
}

-static void create_filter_finish(struct filter_parse_state *ps)
+static void create_filter_finish(struct filter_parse_error *pe)
{
- if (ps) {
- filter_opstack_clear(ps);
- postfix_clear(ps);
- kfree(ps);
- }
+ kfree(pe);
}

/**
@@ -1921,24 +1700,20 @@ static void create_filter_finish(struct filter_parse_state *ps)
* freeing it.
*/
static int create_filter(struct trace_event_call *call,
- char *filter_str, bool set_str,
+ char *filter_string, bool set_str,
struct event_filter **filterp)
{
+ struct filter_parse_error *pe = NULL;
struct event_filter *filter = NULL;
- struct filter_parse_state *ps = NULL;
int err;

- err = create_filter_start(filter_str, set_str, &ps, &filter);
- if (!err) {
- err = replace_preds(call, filter, ps, false);
- if (err && set_str)
- append_filter_err(ps, filter);
- }
- if (err && !set_str) {
- free_event_filter(filter);
- filter = NULL;
- }
- create_filter_finish(ps);
+ err = create_filter_start(filter_string, set_str, &pe, &filter);
+ if (err)
+ return err;
+
+ err = process_preds(call, filter_string, filter, pe);
+ if (err && set_str)
+ append_filter_err(pe, filter);

*filterp = filter;
return err;
@@ -1965,21 +1740,21 @@ static int create_system_filter(struct trace_subsystem_dir *dir,
char *filter_str, struct event_filter **filterp)
{
struct event_filter *filter = NULL;
- struct filter_parse_state *ps = NULL;
+ struct filter_parse_error *pe = NULL;
int err;

- err = create_filter_start(filter_str, true, &ps, &filter);
+ err = create_filter_start(filter_str, true, &pe, &filter);
if (!err) {
- err = replace_system_preds(dir, tr, ps, filter_str);
+ err = process_system_preds(dir, tr, pe, filter_str);
if (!err) {
/* System filters just show a default message */
kfree(filter->filter_string);
filter->filter_string = NULL;
} else {
- append_filter_err(ps, filter);
+ append_filter_err(pe, filter);
}
}
- create_filter_finish(ps);
+ create_filter_finish(pe);

*filterp = filter;
return err;
@@ -2162,66 +1937,79 @@ static int __ftrace_function_set_filter(int filter, char *buf, int len,
return ret;
}

-static int ftrace_function_check_pred(struct filter_pred *pred, int leaf)
+static int ftrace_function_check_pred(struct filter_pred *pred)
{
struct ftrace_event_field *field = pred->field;

- if (leaf) {
- /*
- * Check the leaf predicate for function trace, verify:
- * - only '==' and '!=' is used
- * - the 'ip' field is used
- */
- if ((pred->op != OP_EQ) && (pred->op != OP_NE))
- return -EINVAL;
+ /*
+ * Check the predicate for function trace, verify:
+ * - only '==' and '!=' is used
+ * - the 'ip' field is used
+ */
+ if ((pred->op != OP_EQ) && (pred->op != OP_NE))
+ return -EINVAL;

- if (strcmp(field->name, "ip"))
- return -EINVAL;
- } else {
- /*
- * Check the non leaf predicate for function trace, verify:
- * - only '||' is used
- */
- if (pred->op != OP_OR)
- return -EINVAL;
- }
+ if (strcmp(field->name, "ip"))
+ return -EINVAL;

return 0;
}

-static int ftrace_function_set_filter_cb(enum move_type move,
- struct filter_pred *pred,
- int *err, void *data)
+static int ftrace_function_set_filter_pred(struct filter_pred *pred,
+ struct function_filter_data *data)
{
+ int ret;
+
/* Checking the node is valid for function trace. */
- if ((move != MOVE_DOWN) ||
- (pred->left != FILTER_PRED_INVALID)) {
- *err = ftrace_function_check_pred(pred, 0);
- } else {
- *err = ftrace_function_check_pred(pred, 1);
- if (*err)
- return WALK_PRED_ABORT;
-
- *err = __ftrace_function_set_filter(pred->op == OP_EQ,
- pred->regex.pattern,
- pred->regex.len,
- data);
- }
+ ret = ftrace_function_check_pred(pred);
+ if (ret)
+ return ret;
+
+ return __ftrace_function_set_filter(pred->op == OP_EQ,
+ pred->regex.pattern,
+ pred->regex.len,
+ data);
+}
+
+static bool is_or(struct prog_entry *prog, int i)
+{
+ int target;

- return (*err) ? WALK_PRED_ABORT : WALK_PRED_DEFAULT;
+ /*
+ * Only "||" is allowed for function events, thus,
+ * all true branches should jump to true, and any
+ * false branch should jump to false.
+ */
+ target = prog[i].target + 1;
+ /* True and false have NULL preds (all prog entries should jump to one */
+ if (prog[target].pred)
+ return false;
+
+ /* prog[target].target is 1 for TRUE, 0 for FALSE */
+ return prog[i].when_to_branch == prog[target].target;
}

static int ftrace_function_set_filter(struct perf_event *event,
struct event_filter *filter)
{
+ struct prog_entry *prog = filter->prog;
struct function_filter_data data = {
.first_filter = 1,
.first_notrace = 1,
.ops = &event->ftrace_ops,
};
+ int i;
+
+ for (i = 0; prog[i].pred; i++) {
+ struct filter_pred *pred = prog[i].pred;
+
+ if (!is_or(prog, i))
+ return -EINVAL;

- return walk_pred_tree(filter->preds, filter->root,
- ftrace_function_set_filter_cb, &data);
+ if (ftrace_function_set_filter_pred(pred, &data) < 0)
+ return -EINVAL;
+ }
+ return 0;
}
#else
static int ftrace_function_set_filter(struct perf_event *event,
@@ -2364,26 +2152,27 @@ static int test_pred_visited_fn(struct filter_pred *pred, void *event)
return 1;
}

-static int test_walk_pred_cb(enum move_type move, struct filter_pred *pred,
- int *err, void *data)
+static void update_pred_fn(struct event_filter *filter, char *fields)
{
- char *fields = data;
+ struct prog_entry *prog = filter->prog;
+ int i;

- if ((move == MOVE_DOWN) &&
- (pred->left == FILTER_PRED_INVALID)) {
+ for (i = 0; prog[i].pred; i++) {
+ struct filter_pred *pred = prog[i].pred;
struct ftrace_event_field *field = pred->field;

+ WARN_ON_ONCE(!pred->fn);
+
if (!field) {
- WARN(1, "all leafs should have field defined");
- return WALK_PRED_DEFAULT;
+ WARN_ONCE(1, "all leafs should have field defined %d", i);
+ continue;
}
+
if (!strchr(fields, *field->name))
- return WALK_PRED_DEFAULT;
+ continue;

- WARN_ON(!pred->fn);
pred->fn = test_pred_visited_fn;
}
- return WALK_PRED_DEFAULT;
}

static __init int ftrace_test_event_filter(void)
@@ -2413,9 +2202,7 @@ static __init int ftrace_test_event_filter(void)
*/
preempt_disable();
if (*d->not_visited)
- walk_pred_tree(filter->preds, filter->root,
- test_walk_pred_cb,
- d->not_visited);
+ update_pred_fn(filter, d->not_visited);

test_pred_visited = 0;
err = filter_match_preds(filter, &d->rec);
--
2.15.1